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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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Old 06-18-2015, 07:51 AM
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Performance caliper slide pins & bushings any better than stock?

Are these any better than stock? Anyone has any experience with similar or same product? Comments? Waste of $$ or money well spent?

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Old 06-18-2015, 08:33 AM
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The factory rubber bushing design allows for deflection in the caliper, but no real service requirements. Caliper deflection can cause uneven pad wear and less than amazing pedal feel.

Our design removes the caliper deflection which enhances pedal feel, it also causes the caliper to slide in and out evenly which prolongs pad life by providing equal pressure across the entire pad. Unlike other solid bushings our design is a sealed system, this is going to stretch your service interval far beyond the typical solid open end brass bushing design and allow the service interval to be comparable to most street pads life. Servicing is simple remove, clean, grease, reinstall, a very simple process when changing brake pads.

-James
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Old 06-18-2015, 08:53 AM
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They may be okay, but they do need periodic cleaning and relubing.

A solution looking for a problem.
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Old 06-18-2015, 09:37 AM
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Let's take these one at a time.

Quote:
Originally Posted by doru View Post
Are these any better than stock?
I should hope so; but quantify "better." According to ECS, they "reduce deflection," which is always a good thing. Reduced deflection (movement of the braking components) should improve initial bite and "pedal feel" (firmer, more distinct engagement point). But at what cost? It seems like a potential squeak spot to me, especially in the braking system.

Quote:
Originally Posted by doru View Post
Anyone has any experience with similar or same product? Comments?
I installed the standard guide bushings about 10k miles ago, and I have no complaints. Of course, I'm not tracking or autocrossing my car, so I'm not super sensitive to changes in my brakes. I also went with cheaper Meyle rotors and Akebono Euro ceramic pads (ZERO DUST!!!!!), which did reduce the initial brake bite somewhat.

Quote:
Originally Posted by doru View Post
Waste of $$ or money well spent?
It really depends on what you want from your braking system. I think you might be wiser to save up for a system like the ECS big brake kit for our e39s, as it will have been designed for high performance out of the box. Our e39s, like it or not, are primarily designed for comfort and daily drivability. However, if you want a firmer pedal and more consistent brake wear, with some extra stability and aren't afraid to do it yourself, this seems like a reasonably priced upgrade for the standard braking system. I, however, will be saving up for the big brake kit.
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Old 06-18-2015, 10:44 AM
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Old 06-18-2015, 10:45 AM
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Quote:
Originally Posted by edjack View Post
They may be okay, but they do need periodic cleaning and relubing.

A solution looking for a problem.
This is what I was looking for.
Big turn-off having to service these things on a regular basis.
My calipers are serviced "regularly", but this is just rebuilding them when I change the rotors & pads and the brake fluid flush every 2 years. I don't want to do more if not necessary, which this set seem to need.

Thx Ed & Computinateor
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Old 06-18-2015, 10:56 AM
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I admit, I have done my brakes two or three times on my 2002 and I didn't even KNOW there were bushings around my caliper pins!

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Old 06-18-2015, 11:01 AM
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Quote:
Originally Posted by edjack View Post
They may be okay, but they do need periodic cleaning and relubing.

A solution looking for a problem.
+1, the idea looks great and at a couple points over the years (when I was due for pad changes) I was going to order these (or one of the competing, but similar products) and did not, due to a few negative posts from folks that used them. I forget off hand what the issues where, but I think it did have to do with actually more frequent service or they had issues. One guy posted he even went back to the stock guide pins/bushings. I asked a couple BMW techs about it...they shrugged their shoulders, basically had no opinion...saying there were some advantages, but also some negatives...again, don't recall the specifics. Sorry if this post is not more helpful....my opinion is to leave this stock...

I love ECS Tuning products...get their Exact Fit braided brake lines instead!
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Old 06-18-2015, 11:43 AM
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Originally Posted by 540 M-Sport View Post
I love ECS Tuning products...get their Exact Fit braided brake lines instead!
I'm installing them now!
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Old 06-18-2015, 11:50 AM
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I must be talking to a wall... ive been bitching at you people for years about this... and now?

lol

what do you think?

I have 8 sets of those.. and they fit on every bmw between 82 to current

only 2 cent i have to add is dont lube them... the lube will pick up detrius and shorten there life..

They are machined they dont need lube, they are also soft... do not hammer with anything on them.. when you do it right they will push in by hand.. the external C clip is what keeps em on the car,

i also made a set my self with a material called Amco.. almost the same stuff as what people who sell em are made with, just a little more hardness



I think these ones last longer... but your gonna have to find that out for your self...
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Old 06-18-2015, 12:14 PM
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I have thought about getting those brass caliper pins...
To help against any slushy pedal feel.
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Old 06-18-2015, 01:56 PM
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Quote:
Originally Posted by ECSTuning View Post
Caliper deflection can cause uneven pad wear and less than amazing pedal feel.
Quote:
Originally Posted by Jason5driver View Post
I have thought about getting those brass caliper pins...
To help against any slushy pedal feel.
When I hear adverbs being applied to brake feel, I have trouble identifying with those feelings.

But, while my hearing may be bad, I can see caliper pins, and uneven pad wear on my own vehicle.
- One user's example of a complete brake job with all torque figures, specs, measurements, fluids, decisions, tools, tricks, mistakes, suppliers, costs, etc., that it entails (1)

I just removed the wheels from my fronts, which desperately need new pads.
So, since I'm just about to start a front brake job ... how would I know whether my stock original bushings are in good shape or not?
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Old 06-18-2015, 02:25 PM
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Quote:
Originally Posted by bluebee View Post
When I hear adverbs being applied to brake feel, I have trouble identifying with those feelings.

But, while my hearing may be bad, I can see caliper pins, and uneven pad wear on my own vehicle.
- One user's example of a complete brake job with all torque figures, specs, measurements, fluids, decisions, tools, tricks, mistakes, suppliers, costs, etc., that it entails (1)

Here are my last-replaced rears, for example, which show uneven wear:


I just removed the wheels from my fronts, which desperately need new pads.
So, since I'm just about to start a front brake job ... how would I know whether my stock original bushings are in good shape or not?

Blue, that's why I replace the rubber bushings every time I change the brake discs & pads (together with a complete caliper rebuild). Also, every 2 years when I flush the brake fluid, I take the pins out & clean them. In time, I noticed the rubber degrades and starts leaving deposits on the slide pins. I thought this product being metallic, I won't have that issue, but as it turns out, there is more maintenance involved than I am willing to do. And I also observe the TIS which states NOT to use lube on the slide pins. My car never exhibited that uneven wear, but I can attest that by the time I need to do the brake fluid flush, that the calipers don't move as freely - that's the reason I take out the pins & clean them (rubber deposit). For my car, the p/n is 34111157038 if you go with ATE (about 13$/set) or p/n 34216869617 if you go with OE BMW (which is essentially the same), but costs about 31$/set. My slide pins are still original, shiny and work well.
Another culprit for uneven wear could be a busted piston. This is the reason I rebuild the calipers every now and then - they are main safety component. If the piston starts to rust ever so slightly, or due to that getting pitted, the best bet is to trash it and buy a brand new brake caliper. Centric is manufacturing some decent calipers that don't break the bank.

0.02
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Old 06-19-2015, 07:43 AM
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Quote:
Originally Posted by doru View Post
...
Another culprit for uneven wear could be a busted piston. This is the reason I rebuild the calipers every now and then - they are main safety component. If the piston starts to rust ever so slightly, or due to that getting pitted, the best bet is to trash it and buy a brand new brake caliper. Centric is manufacturing some decent calipers that don't break the bank.

0.02
Do you mean Centric is producing brand new calipers, or remanufacturing? If new, where are they available? I've haven't ever noticed listings for new, Centric calipers.

I do agree that it's a good idea to very carefully check piston condition before retracting them back into the caliper bore when installing new pads. Which of course means folding back the dust boot, which is a good opportunity to check for splits & cracks.

Another option is a DIY rebuild - new piston & seal kit. Rock Auto sells E39 pistons from Centric.

A few years ago I saw an article describing why a re-manufactured caliper may not be a good idea. Many premium caliper OEMs apply a coating to the caliper cylinder, usually zinc plating, which provides some "slipperiness" for piston movement. Reman vendors usually clean returned cores with shot or glass bead. That treatment removes the zinc layer leaving the base metal (iron or aluminum) exposed. The slight stickiness & hangups as the piston moves back and forth would promote cocking in the bore and accelerate wear & reduced life for the remanufactured caliper. BTW, not a safety issue - the caliper will still work, just not as long as an original.

It made sense to me so I've since either bought new or done my own rebuild.
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Old 06-19-2015, 08:08 AM
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RDL, so far I did rebuild all my calipers - the pistons were in great shape. If for a reason I will ever find a pitted or scratched piston, I will replace that caliper. A new OE (ATE) caliper is anywhere from 275$/side to 330$/side. Remanufactured are around 130$ or so. These are for the fronts.

Below is the Centric table with the equivalent:

2003 BMW 530i

8 Record(s) found *******>********>
Part DescriptionFlavorNotesNotesPositionPart No.FnPer Car QtyPic
Caliper KitsBrake Caliper Repair KitE39 Front143.42008
2
Caliper KitsBrake Caliper Repair KitE39 Rear143.34018
2
Caliper PistonSteel & Aluminum Caliper Pistons Front146.60009
60mm Piston1
Caliper PistonSteel & Aluminum Caliper Pistons Rear146.40023
40mm Piston2
CalipersPosi-Quiet Loaded CaliperE39 Front Left142.34098
1
CalipersPosi-Quiet Loaded CaliperE39 Front Right142.34097
1
CalipersPosi-Quiet Loaded CaliperE39 Rear Left142.34546
1
CalipersPosi-Quiet Loaded CaliperE39 Rear Right142.34545
1
1

If buying a centric remanufactured caliper, they cost around 75$ - 80$/side. Centric claims they replace the piston with new ones (here is the link - you have to scroll down a bit to see the piston description), but basically this is what they claim:

*******>********>
All new pistons
Every Posi Quiet brake caliper piston phenolic or steel is replaced to guarantee proper performance throughout the lifetime of the caliper.
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Old 06-19-2015, 08:18 AM
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well actually the piston doesn't contact the walls of the caliper bore but rides on a square cut o ring , all the coating does is protect the inside of the caliper from corrosion for those that don't flush there system as most people don't, but a coating on the piston will protect it from wear that could lead to uneven movement of the piston
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Old 06-19-2015, 09:18 AM
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Quote:
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well actually the piston doesn't contact the walls of the caliper bore but rides on a square cut o ring , all the coating does is protect the inside of the caliper from corrosion for those that don't flush there system as most people don't, but a coating on the piston will protect it from wear that could lead to uneven movement of the piston
I don't agree with "doesn't contact the walls of the caliper." The seal doesn't have the rigidity or span to hold the piston axis true to the cylinder axis.

In operation, any piston cocking will depend on the angles between the caliper ears opposite the piston wrt to the cylinder axis, the ears' contact on the outer pad, any taper in the pads, contact between the piston and the inner pad and the caliper locating pins/bushings alignment with the cylinder. All of these should be true, but aren't necessarily, due to manufacturing tolerances and wear or seizing. The piston clearance is only ~0.2 mm or so & thus even a very small misalignment angle will cockthe piston into contact. For instance, consider a pad frozen/jammed in the caliper carrier bracket, which twists the pad wrt to the caliper - the forces are no longer aligned on the same axis ... and the part with the most compliance to adjust for the mis-alignment is the piston/seal. So the piston gets cocked wrt to the caliper bore & the bottom of the piston (furthest from the seal) is forced into contact with the cylinder bore.

Another illustration. It's fairly common that a piston will jam itself in the bore when one is removing (and later inserting) a piston during a re-build. Which demonstrates that the seal alone is unable to keep the piston axis true to the caliper bore axis.
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Old 06-19-2015, 09:31 AM
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I'm confused.

With the calipers still on the car, and the pins removed, is there any way to easily INSPECT the OEM rubber bushings by eye (to see if they are damaged)?
> E39 (1997 - 2003) > To Lube or not to Lube Brake Guide Pin

Or, must they only be inspected upon caliper removal from the car (which doesn't normally happen in a typical brake job) and with the caliper disassembled?

In addition, I can easily find plenty of in-vitro pictures of replacement OEM (rubber) or redesigned (brass) caliper pin guide bushings, from almost every manufacturer.

But, does anyone have an in-situ picture of their stock rubber oem bushing still inside their partly disassembled oem caliper (like this picture, only for the OEM bushings)?
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Old 06-19-2015, 09:34 AM
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Quote:
Originally Posted by doru View Post
RDL, so far I did rebuild all my calipers - the pistons were in great shape. If for a reason I will ever find a pitted or scratched piston, I will replace that caliper. A new OE (ATE) caliper is anywhere from 275$/side to 330$/side. Remanufactured are around 130$ or so. These are for the fronts.

Below is the Centric table with the equivalent:
...
If buying a centric remanufactured caliper, they cost around 75$ - 80$/side. Centric claims they replace the piston with new ones
...
Doru
Thanks for the data. The ATE calipers sure are expensive. Last year I thought I was going to have to replace fronts due to rusty pistons. I found listings for new ATEs at ~US$150. But that was a real find - one wonders if it wasn't a pricing error.

In the end I found Centric pistons (from Rock Auto) & bought ATE seal kits. The pistons were steel & appeared well made. I've put 20k km & a winter on them with no problems apparent.

EDIT: PS I also found listings for pistons on a UK site. If Rock Auto discontinues the Centric pistons try a Google search. Or post back, I may have saved the link ... somewhere.
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Old 06-19-2015, 10:16 AM
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RDL, thanks. I know one day I will have to replace the calipers (or the pistons at least - which would be more cost-effective). I'm not sure what the size of those pistons is (length / diameter), I know I can throw a caliper and measure them, but once they're out, I need to replace on the spot, it's my DD and I can't wait days/weeks for one part to show up. usually I have some sort of "stock" for what I know I need to replace 100%, or what can fail (and is not very expensive).

Bluebee, the rubber bushings degrade over time and should be changed. Also, they wear as in losing material (inside) over time. They're not very expensive, use the ATE service kit which is about 12-13 bux/side every 4 years or so. The TIS state not to lube the slide pins, because the rubber bushings (new) are coated with a white-ish substance that allow the slide pins to glide. That coating degrades and vanishes over time as well. Doesn't feel like grease.
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Old 06-19-2015, 10:29 AM
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Quote:
Originally Posted by doru View Post
Bluebee, the rubber bushings degrade over time and should be changed. Also, they wear as in losing material (inside) over time.
It makes sense that the rubber bushings degrade, but I haven't seen a photo of one in an E39 caliper, let alone a degraded on inside an E39 caliper.

I have my bimmer up on 4 jacks as we speak, as I was planning on doing my brakes again. I'm just confused as to how to INSPECT them properly.

Must I remove the bushings first?
Does that damage them?
(I don't have a replacement handy.)

Quote:
Originally Posted by doru View Post
They're not very expensive, use the ATE service kit which is about 12-13 bux/side every 4 years or so.
Is this the suggested ATE rubber bushing kit?

Quote:
Originally Posted by doru View Post
The TIS state not to lube the slide pins, because the rubber bushings (new) are coated with a white-ish substance that allow the slide pins to glide. That coating degrades and vanishes over time as well. Doesn't feel like grease.
I wonder if that whitish powder is the same thing (corn starch? talcum powder?) they put on new bicycle inner tire tubes to keep the rubber from sticking in storage/transit/use?
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Old 06-19-2015, 11:27 AM
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Originally Posted by rdl View Post
I don't agree with "doesn't contact the walls of the caliper." The seal doesn't have the rigidity or span to hold the piston axis true to the cylinder axis.

In operation, any piston cocking will depend on the angles between the caliper ears opposite the piston wrt to the cylinder axis, the ears' contact on the outer pad, any taper in the pads, contact between the piston and the inner pad and the caliper locating pins/bushings alignment with the cylinder. All of these should be true, but aren't necessarily, due to manufacturing tolerances and wear or seizing. The piston clearance is only ~0.2 mm or so & thus even a very small misalignment angle will cockthe piston into contact. For instance, consider a pad frozen/jammed in the caliper carrier bracket, which twists the pad wrt to the caliper - the forces are no longer aligned on the same axis ... and the part with the most compliance to adjust for the mis-alignment is the piston/seal. So the piston gets cocked wrt to the caliper bore & the bottom of the piston (furthest from the seal) is forced into contact with the cylinder bore.

Another illustration. It's fairly common that a piston will jam itself in the bore when one is removing (and later inserting) a piston during a re-build. Which demonstrates that the seal alone is unable to keep the piston axis true to the caliper bore axis.
doesn't matter if you agree you are wrong
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  #23  
Old 06-19-2015, 11:50 AM
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doru doru is offline
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Originally Posted by bluebee View Post
It makes sense that the rubber bushings degrade, but I haven't seen a photo of one in an E39 caliper, let alone a degraded on inside an E39 caliper.

I have my bimmer up on 4 jacks as we speak, as I was planning on doing my brakes again. I'm just confused as to how to INSPECT them properly.

Must I remove the bushings first?
Does that damage them?
(I don't have a replacement handy.)


Is this the suggested ATE rubber bushing kit?


I wonder if that whitish powder is the same thing (corn starch? talcum powder?) they put on new bicycle inner tire tubes to keep the rubber from sticking in storage/transit/use?
Get them from ECS - 13$/side linky they are ATE (same as EO, but cheaper):



You don't need to inspect them, just change them. Some times the inner diameter of the caliper that houses the bushings starts rusting, and this can also swell the bushings (pushed by rust), and this will narrow the gliding side of the pin, which "could" start binding - then the rubber starts to get eroded. If you have black rubber residue on the slide pins when you pull them out, you know this is what happens.
You need to take off the caliper. to do that, first loosen the brake line. Be careful and use a flare wrench for that, or you could end up rounding off the hex of the brake line, in which case you're SOL - you will end up replacing the lines.
Have a rubber plug handy for the lines (they look similar with the rubber plugs at the back of the engine, or CCV - google for them "brake line plugs" or similar. They are around 2-3 bux).
Take off the caliper (the carrier can stay in place), unscrew the brake line, and with caliper free, you can squeeze them out - you might need a big screwdriver to pop them lose, but first try a small screwdriver to shear the "cold weld" that formed over the years - you will know.
Clean very well the receptacle of the bushings (rust, dirt), then once done, you can use some lube/grease to slide them in. When you are done make sure you bleed the brakes.
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Last edited by doru; 06-19-2015 at 11:53 AM.
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  #24  
Old 06-22-2015, 04:28 AM
rdl rdl is offline
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Quote:
Originally Posted by Edge540 View Post
doesn't matter if you agree you are wrong
Well, on a simple calculation I make it that anything other than perfect alignment in the caliper/pads/mounting would result in a cocking torque of 500+ lb-ft on the front piston during maximum braking effect. Do you really think that the seal (of what, 3 mm width?) could resist this torque? With less than ~0.25 degree of deflection before the piston contacts the cylinder bore?
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Old 06-22-2015, 09:05 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by rdl View Post
Well, on a simple calculation I make it that anything other than perfect alignment in the caliper/pads/mounting would result in a cocking torque of 500+ lb-ft on the front piston during maximum braking effect. Do you really think that the seal (of what, 3 mm width?) could resist this torque? With less than ~0.25 degree of deflection before the piston contacts the cylinder bore?
Do you think, perchance, that a severely cocked alignment could possibly have caused this anomaly today?
> E46 (1999 - 2006) > Brake clunk & squealing
Quote:
Originally Posted by 968RACER View Post
I've been hearing my brakes squeal with the windows down for quite some time. Also, I would hear a clunk when moving from a dead stop. I took my calipers off for inspection and found that all 4 pads on my front separated from the back plates. These are Pagids that I installed a couple of years ago and have about 7000 mostly highway miles. Needless to say, I did not replace them with Pagids again. As you can see I had plenty of life on the friction material. Glad I caught these when I did.
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