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My rearend is leaking (not a personal problem, I posted that on the other forum).
I haven’t jacked the car up, yet, but I did reach under and while there is a drop on the drain plug it seems to be leaking from either the pumpkin gasket or pinion seal. So, two questions: I didn’t think a C1 had a differential drain plug? What is the best way to jack up just the rear?
It would be easier if it were the drain plug.....Housing gasket....No help! I had to replace the pinion seal and nut (there was no nut????)...No problem since..... 1000 fairly hard miles.
I would block the front wheels and lift from jacking points in front of the rear wheels on the frame flat. Don't necessarily go by that... I have a scissor lift..........Run up stands would be (IMO) the best lift practice.
Others will offer suggestions.........Oh, by the way if and when you get under the car...look for 90 weight gear oil coverage under the car floor/drive shaft pinion area.....That would be the pinion seal.
It would be easier if it were the drain plug.....Housing gasket....No help! I had to replace the pinion seal and nut (there was no nut????)...No problem since..... 1000 fairly hard miles.
I would block the front wheels and lift from jacking points in front of the rear wheels on the frame flat. Don't necessarily go by that... I have a scissor lift..........Run up stands would be (IMO) the best lift practice.
Others will offer suggestions.........Oh, by the way if and when you get under the car...look for 90 weight gear oil coverage under the car floor/drive shaft pinion area.....That would be the pinion seal.
Dcamick
pinion seal leaks are apt to show up like this from being slung.
as to jacking, "I" would make a softener for my floor jack pad to go up against the differential and continue to jack there
So I shimmied under the car to take a look and it appears to be the pinion seal based on all the oil on my shiny new mufflers. I ordered a new seal and will get to it next weekend. Fortunately, it’s a relatively easy job on a C1.
there is a crush sleeve on the pinion gear shaft between the flange and the shoulder on the gear that determines bearing preload. you don't need to replace this but you do need to take care not to over tighten it so that it compresses. one way to do this is to use a torque wrench to determine what torque it takes to JUST tighten the nut a smiggen (a technical term). then remove the nut, etc, replace the seal and then retorque to the torque you pre-determined.
there may be other ways, if so someone will chime in.
Thanks, Bill, what I’ve done in the past is to count the threads and mark the current position of the pinion nut and then return it to that position once the seal has been replaced.
Thanks, Bill, what I’ve done in the past is to count the threads and mark the current position of the pinion nut and then return it to that position once the seal has been replaced.
Thanks, Bill, what I’ve done in the past is to count the threads and mark the current position of the pinion nut and then return it to that position once the seal has been replaced.
Curious question, Do you plan to drop the pumpkin to do this job or leave it on the car? Mine leaks but not enough yet that I'm ready to deal with it.
Leave it in the car (on a C2 this is virtually impossible). Car on jack stands in the back with catch pan under pinion, check the rear u-joint for slop, remove two rear u-joint u-bolts and slide driveshaft to the side (support it so it doesn’t hang), check the pinion for any slop (ensures the bearing is good), count the number of pinion threads that stick out past the nut and mark the nut and yoke, hold the pinion yoke and remove the nut with an impact wrench, inspect the area on the yoke where the seal rides for any wear (if so, either sleeve or replace), remove the old seal and allow the diff to finish draining and clean the area thoroughly, remove all sealant and oil/grease from the pinion splines, diff seal recess and yoke (preserve the marks you made!), spread sealant on the outer edge of the new seal where it will contact the diff housing and install the seal, spread a light coat of grease or gear oil on the inside of the seal, spread sealant on the inside of the yoke splines and push the yoke on as far as you can by hand, install the nut and torque it until the counted number of threads are exposed and the marks you made are aligned, reinstall the driveshaft (be very careful not to overtorque the nuts and crush the u-joint caps), refill the rear and you are good to go!
ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL 57-61 Chevy axle housings (BOTH pass car and Corvette) have a drain plug. It was no longer in 62-later axle housings (I suspect this was a bean counter .05cent savings!!!).
I see no oil running along the bottom of your rearend center section. Are you positive the oil that has been slung onto the mufflers has not come from the U-joint??? That is fairly common after greasing the rear U-joint.
Thanks, Tom, while I haven’t jacked it up yet, there was a pool of gear oil on the garage floor, oil dripping from the drain plug (lowest point), and oil running down the pumpkin from the pinion in addition to what you see on the mufflers. Interestingly, this rear end was completely rebuilt 9 years ago and just started leaking after my 200 mile round trip to Austin in 100+ degree heat. I’m not sure if its related, but it seems awefully coincidental.
Last edited by Factoid; 08-14-2018 at 10:47 AM.
Reason: my crappy spelling!
Thanks, Tom, while I haven’t jacked it up yet, there was a pool of gear oil on the garage floor, oil dripping from the drain plug (lowest point), and oil running down the pumpkin from the pinion in addition to what you see on the mufflers. Interestingly, this rear end was completely rebuilt 9 years ago and just started leaking after my 200 mile round trip to Austin in 100+ degree heat. I’m not sure if its related, but it seems awefully coincidental.
Well, with that information, it sounds like a pinion seal leak. Only one way to fix that. Sorry.
If the drain plug is leaking, then a new drain plug gasket is in order. The same gasket that fits the oil pan drain plug will work for the drain plug on the axle housing.
I see no oil running along the bottom of your rearend center section. Are you positive the oil that has been slung onto the mufflers has not come from the U-joint??? That is fairly common after greasing the rear U-joint.
that's where the stain on my mufflers came from....
Bill
08-13-2018, 02:22 PM
1961 Differential Question
