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fixing fuel leaks

2K views 2 replies 3 participants last post by  89 325i 
#1 ·
i am currently repairing multiple fuel leaks on and around my fuel tank and am wondering if their is a possibility that someone who has removed the fuel tank on a 1986 325 or like model would be able to send me a walk through of what i need to do to remove it and what i should expect. any help in this area would be greatly appreciated.
 
#2 ·
b1crewchief said:
i am currently repairing multiple fuel leaks on and around my fuel tank and am wondering if their is a possibility that someone who has removed the fuel tank on a 1986 325 or like model would be able to send me a walk through of what i need to do to remove it and what i should expect. any help in this area would be greatly appreciated.
Just took one out of a 1987 325. You might consider buying a Bentley BMW 3-Series Service Manual. There are some used ones out on e-bay.
You will have to take off your exhaust from the catalytic converter. Then remove the heat shields that cover the driveshaft. Then mark your drive shaft at both the front and rear with some form of model paint. This will allow you to put it back on the way it came off. Otherwise it will be out of balance. Loosen the center support two bolts, loosen the clamping sleeve in the middle. Don't remove the clamping sleeve just take it to the end. This is just behind the middle support bracket on the rear part of the driveshaft. This will allow you to push the drive shaft forward enough to take off the rear part of the drive shaft (don't let it bend or hang down). Then take off your driveshaft, you will have to pull it down in the center not to far but enough to allow the front part to come off the transmission then slide it forward and pull off the back section. Try and let it come down as level as possible to avoid putting to much pressure on the center section. Once you have that off and everything removed. The exhaust has some mounting brackets that attach to the top of the tank. You will be able to take them off when you have the tank out. Drain the tank, leave the center connection line on. Remove the back seat in your car remove inspection plate and then remove the fuel transfer pump, sending unit and all fuel lines both from and return lines from the top of the tank. Then remove the feeder hose from your fill side. Now you will have 3 bolts and one nut to remove on the tank. Once there off the tank will come down towards the front of the car. It isn't heavy but be prepared for some rust and dirt to come with it. Once it is down in the front you will have a return hose on the drivers side to disconnect. The main feeder hose to your fuel pump may be taped to the top. Once down you will be able to see it.
It's a job but I took it out in a couple of nights after work. Plan on buying some liquid wrench and spray everthing for about 24 hours before you start trying to loosen things. I only had to cut off two nuts and they where on the exhaust bracket. I didn't want to use heat because I had leaks with a lot of fumes. I also bought all new nuts and bolts ($11.00) and put WD40 on all of threads. Use some litihum grease for your driveshaft when putting it back on the transmission spindle. With the tank out I checked, cleaned all of the brake lines and wiring that sits above the tank. It will save you a lot of work from having them go bad. You just reverse everything to put it back in. No special tools other than a torgue wrench (final drive is 72 nm or 53ft lb,depending on the size of nut yours is probably a 12M then it's 123nm or 91 ft lb these can vary to 34 ft lb for a 8M). If you don't have Torque wrench it's just get it real tight.
It's to bad that BMW didn't put in a large inspection plate under the rear seat and allow the tank to be removed from the rear inside of the car. Sure would have made things a lot easier.
Hope that helps and good luck.
 
#3 ·
Cef5917 said:
Just took one out of a 1987 325. You might consider buying a Bentley BMW 3-Series Service Manual. There are some used ones out on e-bay.
You will have to take off your exhaust from the catalytic converter. Then remove the heat shields that cover the driveshaft. Then mark your drive shaft at both the front and rear with some form of model paint. This will allow you to put it back on the way it came off. Otherwise it will be out of balance. Loosen the center support two bolts, loosen the clamping sleeve in the middle. Don't remove the clamping sleeve just take it to the end. This is just behind the middle support bracket on the rear part of the driveshaft. This will allow you to push the drive shaft forward enough to take off the rear part of the drive shaft (don't let it bend or hang down). Then take off your driveshaft, you will have to pull it down in the center not to far but enough to allow the front part to come off the transmission then slide it forward and pull off the back section. Try and let it come down as level as possible to avoid putting to much pressure on the center section. Once you have that off and everything removed. The exhaust has some mounting brackets that attach to the top of the tank. You will be able to take them off when you have the tank out. Drain the tank, leave the center connection line on. Remove the back seat in your car remove inspection plate and then remove the fuel transfer pump, sending unit and all fuel lines both from and return lines from the top of the tank. Then remove the feeder hose from your fill side. Now you will have 3 bolts and one nut to remove on the tank. Once there off the tank will come down towards the front of the car. It isn't heavy but be prepared for some rust and dirt to come with it. Once it is down in the front you will have a return hose on the drivers side to disconnect. The main feeder hose to your fuel pump may be taped to the top. Once down you will be able to see it.
It's a job but I took it out in a couple of nights after work. Plan on buying some liquid wrench and spray everthing for about 24 hours before you start trying to loosen things. I only had to cut off two nuts and they where on the exhaust bracket. I didn't want to use heat because I had leaks with a lot of fumes. I also bought all new nuts and bolts ($11.00) and put WD40 on all of threads. Use some litihum grease for your driveshaft when putting it back on the transmission spindle. With the tank out I checked, cleaned all of the brake lines and wiring that sits above the tank. It will save you a lot of work from having them go bad. You just reverse everything to put it back in. No special tools other than a torgue wrench (final drive is 72 nm or 53ft lb,depending on the size of nut yours is probably a 12M then it's 123nm or 91 ft lb these can vary to 34 ft lb for a 8M). If you don't have Torque wrench it's just get it real tight.
It's to bad that BMW didn't put in a large inspection plate under the rear seat and allow the tank to be removed from the rear inside of the car. Sure would have made things a lot easier.
Hope that helps and good luck.
What did you cut the two nuts off with? That's kind of my main fear - rusted stuff that I can't muscle apart. And thanks for the nice instruction manual on this. Appreciated.
 
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