[Neil Martin]

Just returned to LA from Monterey weekend with the wife in our 67 Sprint GT. Car was perfect all weekend. At the off ramp for home had to pump the brakes, but after one pump had brakes. One mile off the freeway a bit of smoke from the back left. Got home and the left rear wheel is really hot.

Let the car sit for an hour. Brakes are now good. Drives fine. Put it in the garage on the hoist and looking from underneath I see what looks like a leak from the left rear axle seal area. When I grab the disk and try and shake it has no play. It ran fine right to the door. But something was leaking. I am thinking maybe the rear bearing was in the early stages of letting go?

I have had a LSD rear end of uncertain pedigree sitting around for 10 years or more, and I figure rather than fuss with the old rear end it is time for a swap. Is there anyone recommended in LA that can go through that rear end to make sure all is well? If it has to be shipped can anyone on the board recommend a good shop?

Thanks

Neil

 

[Neil Martin]

Here's a picture of the leak. Any ideas for a quick interim fix?

 

[frogeye]

Is it possible you have 2 leaks here - both the rear caliper (looks damp near the pipe nut entering the caliper) and the halfshaft seal? Main leak appears to be halfshaft seal and is not too big a job... Matt

 

[brad fischer]

Sounds like your left rear caliper is dragging heating up the wheel and boiling fluid causing you to pump the brakes, and possibly causing the rear wheel seal failure.

 

[Neil Martin]

Thanks

What are the likely causes of the caliper dragging? (Can't be the emergency brake - it does not hold on the best of days)

 

[frogeye]

Thanks

What are the likely causes of the caliper dragging? (Can't be the emergency brake - it does not hold on the best of days)

If it is this, then a caliper piston could be seized. Matt

 

[Alfajay]

Sounds like your left rear caliper is dragging heating up the wheel and boiling fluid causing you to pump the brakes, and possibly causing the rear wheel seal failure.

I think Brad's diagnosis is correct. If the car has ever been parked outdoors and/or not driven regularly, the caliper pistons are likely to have rusted a bit and frozen to the seals. Swapping in a used differential of unknown provenence is unlikely to solve the problem.

As Brad suggests, the heat generated is likely to have caused the oil seal to fail. Repairing the existing caliper and seal is the best solution - neither are big jobs. Removing the stuck piston will be the hardest step - there are LOTS of threads on the BB that discuss this.

 

[jamieandthemagi]

If you find the pistons are caught, once refurbed, take a dremel to the outer ridge in the caliper piston bore, its such a close tolerence I found these used to rust to the piston and cause regular piston seizure

 

[gigem75]

I've never seen halfshafts on a live rear axel sorry couldn't resist but it's true. The bearing is separate from the seal so you should and it's not hard to replace the seal on the one you have on there and then address the caliper. Usually if it's dragging it will heat up and drag creating heat you can smell. then rebuild the calipers if indeed they are leaking. I do know the caliper pistons are a smaller diameter and use a specific seal. Actually I think I have a set of the smaller calipers from the non lsd difs lying around somewhere. Or maybe a good flush of the system will be all you need. As far as using an lsd dif, I wouldn't put it in without replacing the bearing and seals. rear bearings are a *****. Since the lsd difs have different rear calipers you should have them on your spare dif otherwise you'll need to source a set. Someone correct me if I'm wrong about that because to be honest I'm not sure.

 

[Neil Martin]

Update

Well, thank you all.

The left rear caliper had one piston stuck. The oil seal was in 3 pieces.

I got rebuilt calipers from Centerline and put it back together.

One question - does the outer rear bearing get any kind of grease? It didn't look like it should.

Thanks

Neil

 

[Alfajay]

One question - does the outer rear bearing get any kind of grease? It didn't look like it should.

Neil:

The bearings are sealed. As long as yours turns smoothly and don't have any play, you can just reassemble the axles/bearings as-is.

Be careful re-inserting your axles into the tubes as they pass through the grease seal. You don't want the weight of the axles rubbing against the lip of the seal as they go in - you can wear a notch in the seal that way (and no, I've never done that myself).

 

[gigem75]

keep an eye on that area at the bottom of the axle. If it keeps getting wet your rear seal is leaking. It sure does look like it from the photo. There is a weep slot in the disc cover right where it looks like it's leaking. I would certainly check the level in the rear end just to be safe.