I needed to replace the seal on my rear axle on my '25 T coupe -- was leaking some onto my brakes (I have older rocky mountain brakes, that were set up to operate with the hand brake lever).
But first, I pulled the differential plug and the grease began running out. So, I now know I have engine oil leaking into the rear end.
Then, I noticed some sparkling in the oil when the sun hit it. Looks like some super tiny flecks of brass. There was also a little in the grease on the wheel bearing. But, after cleaning and inspecting, the bearing still looks like it is very good condition.
I need some guidance at this point. This is my first attempt at any work on a rear axle.
1. Does this mean that I have something torn up inside the differential?
2. If so, can I still drive it on a short distance? I am having all my outside concrete replaced around my house next week, including my garage floor, and will need to move the car to another location to park it.
3. From researching past threads, I assume I will have to replace the 4th main seal to stop the engine oil from leaking into the differential. Can this be done with the engine still in the car?
4. Is there a way to clean off my brake pads, or will I need to replace them?
1. Sparkly oil says yes, probably.
2. Define short. A few feet will probably be OK. Take it slow and avoid turns, especially sharp turns. Several blocks may be OK, or maybe not. No way to know.
3. I'll pass this one to somebody with more experience in that department.
4. A good solvent like lacquer thinner should get the oil off.
Better take a look at this: http://dauntlessgeezer.com/DG79.html
Scott, something is most likely damaged in the rear end. I would not drive the car if it were mine. If the rear end fails your foot brake won't work and might cause a lot more damage. There is no 4th main seal but, there is a soft plug in the driven plate shaft. The engine must be remove to replace this plug.
Thanks Steve and Stephen! Looks like I've got some work ahead of me.
What makes you think that there is something wrong? The rear end is supposed to have oil, not grease. Perhaps too much..you don't say. There is no 4th main seal. Flecks of brass (or steel) could come from anywhere. How much? Just long term wear. Is there a problem with the rear end other than the leaky wheel seal?
I would think flecks of brass is a good sign, that would mean you've got brass thrust washers inside and it's likely someone has replaced the failure prone babbitt thrusts originally fitted by Ford.
Extra oil flowing into the rear end is better than too little oil, can be fixed with a rebabbitted fourth main - or perhaps temporarily by screwing in the grease cups at the U-joint lots of times?
I think there's a chance you can get by with neoprene seals on the inside of the outer Hyatt's in the rear axle?
Check the oil level in the rear axle often until you've checked/changed the fourth main.
John and Roger may be right. It may be perfectly OK. You don't know until you look.
A worn 4th main can allow oil to leak into the rear end. It can be replaced by pulling the rear end/drive tube assembly. While the rear end is out you can then disassemble and inspect the insides. Babbit thrust washers can cause a metal flake appearance to the oil as they disintagrate, so this is your opportunity to replace them with bronze ones. Be sure to follow the Ford Service Manual and the MTFCA book on rebuilding the rear end.
I would suspect either the sealing washer in the driven plate is missing or the 4th main is worn out. However, it could be just that you have overfilled the engine oil. Oil level should be between the lower and upper petcock. If it is above the upper petcock, it is overfilled. If you go up a lot of hills, that could also contribute to engine oil getting into the rear axle. Brass flecks could come from a timing gear if you have a bronze gear, it could also come from the transmission bushings or from bronze thrust washers in the rear axle. To test for worn with thrust washers, jack up both rear wheels with the parking brake off pull in and out both rear wheels. There should be very little noticeable end play in the axles. If it moves in and out (especially the left side) you need to disassemble the rear axle. Actually you will need to at least pull the axle back in order to check the 4th main, so half the work of disassembly will already have been done.
1. Bronze particles in the rear end lube is fairly normal. As long as your side play is minimal it should be o.k. When you check side play, remove the drain plug and actually look at the differential inside to see how much it moves, NOT how much an axle shaft moves in or out.
3. There is no fourth main seal. There IS a plug in the output shaft, beyond the square hole as you're looking into it. If that's gone, you'll get lots of oil running back. For now, just drain off the excess, don't overfill you engine, and see how long it takes for the rear end level to rise to again. Also, excessive 4th main clearance will allow for oil to pass.
4. Lacquer thinner, gasoline, "Brakleen"**. As always, be careful with combustibles!! Use outdoors!!
**In aerosol cans at any auto parts store.
Thanks for the help, all of you. John M., I really didn't know if anything was wrong, it just seemed a little odd to see yellow particles in the rear end. Not something I'm used to seeing. This is the only T I've had, and am quite a bit outside my comfort zone with mechanical repair.
Actually, the car has been running well, and I have not felt, heard, or seen anything that would be considered abnormal with the rear end.
I will check my oil level and the side play. All things being equal, perhaps I'll be able to take it to the OCF this weekend.
Can you find out from previous owners if the babbitt thrust washers have been replaced? If so, the rear axle is probably OK.
First -- Steve, I inherited this car from my father-in-law. He bought it cash deal from someone local named "Jack" about 15-20 years ago. But, I believe he was in the local T club, so I will make some contacts to see what I can find out.
Second -- Got the car back together. Checked for side play. There is almost zero. Everything is really solid. Oil level was too high, so drained some out.
Will see what happens later this afternoon when I have a chance to drive it. Wanted to let the RTV I put on the seal set up a little first.
There is no drain hole in the differential housing, so in most cars the gear oil is poured in when it is installed and added to when low. It can have flecks of bronze or of steel, or if it still has babbit will have flecks of silver color. If everything turns smoothly and no excessive endplay, you probably don't need to do anything about it. However the oil flow down the tube is something else!