TVR Tasmin, Diff Output Rebuild and More Brakes

With show day now only a couple of days away, the rush was on. I had a car on stands, with a diff on the ground. Not ideal.

Having found the shims to be ruined in the last post I ordered a set with a few different sizes from SNG Barratt in the UK, which arrived in record time. At the same time, I also decided that since the diff was on the ground, and I didn’t want to have to pull it out again I would (stupidly) replace the diff output oil seal as that was leaking a few drops every now and then, so ordered a set of new seals.

You can see the aftermath of the seal leaking here. All down the side of the diff. Also note the sweet two battery method for supporting the diff. This thing weighs a ton, so making sure it’s well supported and stable is important.

I did a lot of research into disassembly and reassembly of the output shaft, but by far the best resource was this Youtube video.
https://youtu.be/5i6R0oEq8QQ

The output shaft takes a bit of work to remove. After draining the diff, remove the lock wire and then the bolts holding the flange to the housing. With them removed its a case of using a soft hammer and a pry bar to lever the output shaft assembly out of the housing. I found it easiest to rotate the assembly and lever off the ears with the bolt holes. Eventually it will pop out.

Looking a bit gross

It looks like oil was bypassing the O-Ring, and leaking from the shaft seal.

Disassembly of the assembly isn’t hard. If you want to reuse the bearings and crush tube you will need to mark the nut and shaft (the shaft is SUPER hard and instantly rounded off the end of all my punches) and count the turns as the nut is removed. This is so you can tighten the nut to the same preload.

Next tap down the locking tab, and remove the nut.

The nut is HUGE and will be tight. I used a massive adjustable spanner. The nut requires a 1-7/8″ or 48mm spanner.  I happened to end up with both. The ring spanner is a couple of foot long.

With the nut removed, its time to tap the shaft out. Support the assembly upside down (studs pointing down) from the mounting flange. Now carefully tap the end of the shaft with a soft hammer. This should start by freeing up the inner bearing, which can be removed, and then, in theory, should push the shaft out through the outer bearing, taking the seal with it. In my case this didn’t go as planned, and the outer bearing more or less exploded and all the rollers decided they didn’t want to be part of this anymore.

This ruins any plans of reusing the bearings and crush tube.

So with that in mind, I shot off a quick order to my Jag parts suppliers (Rodney Jaguar Rover Spares) and ordered some new bearings and a couple of crush sleeves.

It turns out this bastard is the reason the bearing came apart

That old crusty thing is the dust shield over the oil seal. Both that shield, and the oil seal were thoroughly rusted in place, so of course couldn’t be popped out with the bearing as it should have. You cant see the state of this with the shaft/flange in place. I used a chisel to remove both

One warning, that dust shield is obsolete now and unable to be supplied. After much research I’m of the opinion it’s not needed, hence why Jag stopped making them and no one remade them. Some other models that use the same diff, and some later cars, don’t seem to use them either. I guess if you can reuse yours, use it, otherwise I went without.

One last thing I needed to do was remove the outer races of the bearings. I used a punch to tap these out

While I waited for parts everything got a good clean in the parts washer. I didn’t bother to strip off the old paint, as I wasn’t going to do the rest of the diff either.

A couple of days later, with new bearings and seals in hand, I set about refitting the new bearings. As mentioned in the video, I too ground down the old outer race and used that to press the new race in. This took off just enough that the old race wouldn’t stick in the housing.

I taped the race to a big socket and used this in the vice to press it in place

And the inner race

Next I packed the new outer bearing and insert it into the housing

Followed by the oil seal. This was a prick to get into the housing.

And then the shaft gets dropped through the bearing and seal, and then it needs to be tapped through the bearing. This takes a bit of whacking. It pays to check against the other output shaft as to how far you need to tap it down. I found it needs to go further down than you would expect, but if you don’t go far enough it will upset everything from the flange outwards (brake disk sitting central in the caliper, and camber). If you go too far I suspect you will get binding on the housing, so take care.

Once the shaft is in, flip it over and drop the new crush tube down the shaft

and then the grease packed inner bearing goes in, followed by the locking plate and nut. Now its time to crush that tube. This takes a hell of a lot of force to do. The spanner I had was too short to get the required leverage, so I used my jack handle instead by placing the nut in the vice and using the studs on the flange to turn it. I protected the studs with some tube offcuts.

In terms of setting the preload I will recommend you watch the above video as he goes into how to correctly set it, using a spring scale. Its not rocket science, but easier to just watch him do it.

Once the tube is crushed and the preload is set, lock down the nut, install the new O-Ring and you’re done.

Reinstall the assembly in the diff. This will take some force with a soft hammer to tap it back in, just make sure the splines line up first.

Now it was time to look at the nice new shims.

Mmm, clean. They come covered in oil, but I chose to also slather them in copper grease to help stop them rusting or sticking in future. I went with the same stack on the right side, which was perfect for disk placement (central in the caliper), but the left side ended up needing another 0.10 shim to align the disk. I’m not sure if maybe it wasn’t centered before I pulled it apart, or if the new rotor is slightly different.

I test fitted the disks with the new shims and still got great runout readings, so proceeded with installing the calipers for the final time. I’m pissed off I have to reuse the old rubber flexi hose. I have a set of nice braided lines en route, but they have gone missing somewhere between the UK and NZ. They’ll probably show up tomorrow…

And the handbrake calipers went on next. I had some nice new brass springs to fit but I just couldn’t free the old ones up, so gave in and fitted as they were. I did replace the two pins that were fitted dry as they had pitting and scoring. New locking tabs were fitted also.

Now it was time for one of the worst jobs I’ve had to do on a car for a long time. Reinstalling the diff.

If the exhaust hadn’t been designed by an idiot it would have been fine, but instead, it had been built in such a way that there isn’t quite enough space to slip the diff with brakes fitted between the two pipes, and it has no flanges, and the two pipes are welded to a bracket…. but we had to try anyway.

On the jack it went (for now)

And into the boot went a bunch of weights (to try and hold the back of the car down since there was no weight in it anymore)

And then the struggle began. First, we tried to just lift it into place. Nope. No go. Wouldnt even get under the car on the jack. After much pissing around (including taking the diff off the jack, and realising we couldn’t get it back on the jack under the car) we eventually wiggled it in on an angle, from the side, on the jack. It got pretty hairy.

Then I tried to lift just the front so I could get the front mount in and use that to pivot the rear into place. Nope. Started to lift the car off the axle stands. Not good.

We had been at this for a couple of hours now and getting pretty tired of it. Everything was fighting us. Even the damn arms were getting in the way. This one ended up being held forward by an axle stand and steadied by a couple of bungee cords attached to the house.

Finally, plan B came into play. I tried to resist, but it just wasn’t going to happen otherwise.

Out came the reciprocating saw. It was cutting time.

With the exhaust now in two pieces, things were looking up

Now we had ample space for the brake calipers to clear the exhaust, and without much more faffing about, the whole lot slid nicely into place. Unfortunately, we kinda ran out of interest here, so sorry for the lack of photos.

We bolted everything back together, and I sent my awesome helper/wife out to get some exhaust sealing tape and cement. She’s a keeper for sure, not only did she return with what I needed, but also brought back some much needed sustenance.

The idea was to use a clamp I purchased earlier for this purpose (always have a plan B), and clamp over the exhaust tape. The tape was to seal the gap, and the clamp to support the pipe and hold it in place. This plan worked well, and it seems we have an exhaust that is in one piece again and doesn’t leak. The longish term plan is to have the exhaust redone anyway as it sits way too low, its too loud, and doesn’t link the two banks so sounds weird.

So, with everything buttoned back up, diff full of oil, rear brakes bled, it was time for a test run.

The brakes are a little spongy, I suspect there is air in the front (the master cylinder level got a bit low in the couple of weeks of sitting without brakes), so will bleed that tomorrow, but the shudder is completely gone. Just smooth (if vague) braking.

Obviously the worst was in the rear brakes, but I still need to replace the front rotors as they have worn undersize and still have excessive runout. Plus, who doesn’t want flash slotted rotors?

Everything seems to be working as it should too, which is promising. At this rate, it will be a push to get the car ready for Sunday, but since we are rolling, and driving again, that’s a big weight off my shoulders. We can do it, it’s so close.