Rear differential nightmare
Posted: Sat Jan 24, 2015 7:34 pm
The 4.111 LSD rear differential in my B4 has been adorned with more pampering and TLC than any R160 differential deserves.
Last year, I had to replace the pumpkin cover that I cracked, and around 6 months ago, the left side seal started leaking.
So, I decided I was going to remove the entire differential from the car and reseal the entire goddamn thing. Every seal and gasket that comes in contact with oil was replaced, including the driveshaft seal, which wasn't even leaking.
Once the new side seals and retainer O-rings were installed, I was VERY, VERY careful to follow the torque specs of the retainer bolts exactly (which are something like 7.6 ft-lbs). Having never messed with differentials before, I was concerned that I was going to overload the bearings and burn them up if I tightened the bolts too much.
Well, apparently, that's not enough torque, and the O-rings on the retainers started sweating.
A few months later, I drove 2 hours to a Subaru dealer in Jacksonville to see a senior master Subaru tech about this fiasco, and I took complete new retainers with seals already in them and new O-rings (and new retainer bolts for the hell of it) and had him install them. He told me I did a very good job other than undertorquing the bolts. He said "yeah, don't go by the FSM on that stuff." Great. Thanks Subaru.
I figured the problem was taken care of, since it was performed by the most qualified Subaru technician there is.
But I got underneath the car last night, just to double-check:
I am beyond pissed off. Sure, it's a minor leak, and people have driven Subarus for years with such an issue without any catastrophic failures. But with the amount of time, money, blood, sweat, and tears I've invested to try to fix it, I feel I have the right to expect the leak to come to a complete 100% stop.
I have a friend who retired from Universal Studios as an engineer on some of the rollercoasters there, especially the running gear, and we had a good talk about bearings and seals and so forth. He told me that since the bearings were tapered and side-loaded rather than at a direct 90ยบ angle, overloading them would be very unlikely, so he said tighten the bolts as much as I need to, within reason of course.
He also suggested that if I do this again, that I soak the new O-rings in brake fluid overnight, which will cause them to swell up slightly, which may help them seal more effectively.
I plan on doing this once and for all within the next couple months or so, and I'll post back with the results.
Last year, I had to replace the pumpkin cover that I cracked, and around 6 months ago, the left side seal started leaking.
So, I decided I was going to remove the entire differential from the car and reseal the entire goddamn thing. Every seal and gasket that comes in contact with oil was replaced, including the driveshaft seal, which wasn't even leaking.
Once the new side seals and retainer O-rings were installed, I was VERY, VERY careful to follow the torque specs of the retainer bolts exactly (which are something like 7.6 ft-lbs). Having never messed with differentials before, I was concerned that I was going to overload the bearings and burn them up if I tightened the bolts too much.
Well, apparently, that's not enough torque, and the O-rings on the retainers started sweating.
A few months later, I drove 2 hours to a Subaru dealer in Jacksonville to see a senior master Subaru tech about this fiasco, and I took complete new retainers with seals already in them and new O-rings (and new retainer bolts for the hell of it) and had him install them. He told me I did a very good job other than undertorquing the bolts. He said "yeah, don't go by the FSM on that stuff." Great. Thanks Subaru.
I figured the problem was taken care of, since it was performed by the most qualified Subaru technician there is.
But I got underneath the car last night, just to double-check:
I am beyond pissed off. Sure, it's a minor leak, and people have driven Subarus for years with such an issue without any catastrophic failures. But with the amount of time, money, blood, sweat, and tears I've invested to try to fix it, I feel I have the right to expect the leak to come to a complete 100% stop.
I have a friend who retired from Universal Studios as an engineer on some of the rollercoasters there, especially the running gear, and we had a good talk about bearings and seals and so forth. He told me that since the bearings were tapered and side-loaded rather than at a direct 90ยบ angle, overloading them would be very unlikely, so he said tighten the bolts as much as I need to, within reason of course.
He also suggested that if I do this again, that I soak the new O-rings in brake fluid overnight, which will cause them to swell up slightly, which may help them seal more effectively.
I plan on doing this once and for all within the next couple months or so, and I'll post back with the results.