Rear wheels wont turn!

[jjbunn]

I've come to re-mounting the rear wheels. I have new brake pistons and pads installed on both. With the drum off, I can rotate the drive shaft easily by hand. When I place the drum in position, I can rotate the dtum, but it's a bit "graunchy", as if it's catching a little around the rim. When I then mount and tighten the wheel to the drum with the nuts, the wheel wont move at all!

Any help diagnosing this problem would be appreciated - probably it's a stupid error on my part!

Julian

PS are the drums "handed" - is it possible I have swapped the drums and they don't interchange well?

[jbcollier]

Drums are not handed.

What model year and type of Europa do you have?

Most models have a brake adjuster which takes a 1/4" AF wrench.  If this is what you have, back off the adjuster before fitting the drum and try again.

The some/most/all TCS models have a wickedly stupid set up with self-adjusting brakes.  The adjuster is part of the brake cylinder:

http://www.canleyclassics.com/triumph-gt6-mkiii-brakes-disc-front-and-drum-rear-front-fitted-from-commission-no-ke12389kf12390-rear-fitted-from-commission-no-ke/kf20000

Back it right off and try again.  If it is fine, adjust so it is not fine again and then back off until it is "just" ok.

If all this doesn't solve your problem, it might be helpful if you told us why you were in there and what repairs you were attempting.

[4129R]

I had to wind in the threaded adjuster fully, after cleaning all the brake dust off, and then by trial and error, wound it out until the drum wouldn't turn, then backed it off a little.

The drums will be a tight fit, and aligning the shoes correctly is essential.

[jjbunn]

'70 S2.

I have the threaded adjuster fully out - thinking that this was the position of smallest diameter across the shoes. So, if the threaded adjuster needs to start off fully in, then that could be my problem. OTOH I have no difficulty mounting the drum over the shoes, so I doubt it's that.

The other thing I wondered is if the new pads are not the right size width-wise ...

[jbcollier]

If you have the adjuster on the backing plate then the shoes should be 1.25" wide.  If the adjuster is part of the cylinder then the shoes are 1.5" wide.

[Roger]

If you have an S2 but shoes for a TCS, you will have interference problems.
If you have the correct 1.25 in shoes, check that they are snug back against the backplate, retained by the steady rests.

[pboedker]

I've come to re-mounting the rear wheels. I have new brake pistons and pads installed on both. With the drum off, I can rotate the drive shaft easily by hand. When I place the drum in position, I can rotate the dtum, but it's a bit "graunchy", as if it's catching a little around the rim. When I then mount and tighten the wheel to the drum with the nuts, the wheel wont move at all!
..

Does the drum catch the brake shoes or the back plate?
If it catches the rear plate, maybe you are missing the outer spacer behind the hub?
Do not remove the hub until your are absolutely sure you mean it. But you should be able to see a 1/4''(?) spacer between the hub and the outer bearing.

BTW, you can tighten the drum without using the wheel (you might need some spacer material between the nuts and the drum). That way the wheel isn't in your way when trying to diagnose the sound/grinding.

[jjbunn]

I've come to re-mounting the rear wheels. I have new brake pistons and pads installed on both. With the drum off, I can rotate the drive shaft easily by hand. When I place the drum in position, I can rotate the dtum, but it's a bit "graunchy", as if it's catching a little around the rim. When I then mount and tighten the wheel to the drum with the nuts, the wheel wont move at all!
..

Does the drum catch the brake shoes or the back plate?
If it catches the rear plate, maybe you are missing the outer spacer behind the hub?
Do not remove the hub until your are absolutely sure you mean it. But you should be able to see a 1/4''(?) spacer between the hub and the outer bearing.

BTW, you can tighten the drum without using the wheel (you might need some spacer material between the nuts and the drum). That way the wheel isn't in your way when trying to diagnose the sound/grinding.

I have the correct 1.25" wide shoes, so now I am worried about the outer spacer.

The drum appears to catch the backing plate, which seems to indicate the drum is too far in when mounted.

Before I got the car, the PO had been messing with the rear suspension, so I am now unsure if I have all the bits. However, the car rolled freely on its wheels when I got it ?!

I'm looking in my workshop manual, but can't see a diagram showing the spacer. Does anyone have a photo?

Thanks!

[jjbunn]

Here is what the assembly looks like:



I am pretty sure there was no outer spacer when I disassembled the hub, so that's weird. If I pull the hub and add a spacer, then it looks like the hub nut would not have enough threads to properly engage, as the hub would be further out.

[Roger]

Not quite. The outer spacer fits over the plain, unsplined portion of the stub axle, whereas the hub can only fit, naturally, on the splined portion.
The outer spacer is essential in clamping together the hub, spacer, outer bearing, inner spacer and inner bearing. You are right, the nut doesn't cover the thread, but there's plenty of engagement.
It's a good job you discovered this, as if you'd driven with it like it is there's a very good chance of losing a wheel. You MUST fit the missing spacer.

[Roger]

By the way, it looks like your drum has been catching on the wheel cylinder.
Are you assembling with the correct grade of Loctite on the splines? I hope so, and you'll need considerable heat to get the hub off again.
If you look at RD Enterprises website, parts manuals, Europa rear suspension, the spacer is part No 18 on the diagram.

[jbcollier]

http://www.lotus-europa.com/manuals/s2parts/d/index.htm

Spacer #16

[Roger]

http://www.lotus-europa.com/manuals/s2parts/d/index.htm

Spacer #16

Sorry, I was reading the TC page. 16 it is.

[jjbunn]

Not quite. The outer spacer fits over the plain, unsplined portion of the stub axle, whereas the hub can only fit, naturally, on the splined portion.
The outer spacer is essential in clamping together the hub, spacer, outer bearing, inner spacer and inner bearing. You are right, the nut doesn't cover the thread, but there's plenty of engagement.
It's a good job you discovered this, as if you'd driven with it like it is there's a very good chance of losing a wheel. You MUST fit the missing spacer.

Thanks! No chance of being able to drive it like this as the wheels wont turn 

I pulled the hub off: here's a photo.



There is no spacer apparent - should it be between the hub and the bearing housing (where the orange ring is)? How thick is the spacer? I wonder if I can turn one on my lathe.

[Roger]

The orange ring is an oli seal and I aasume that the steel ring inside it is the inner ring of the hub bearing. The spacer is the same OD as that bearing inner ring.
It looks to me as though your stub axle is too far inside that bearing, because I think the plain portion of the stub axle, i.e. inboard of the splines, should protrude from the bearing. The spacer sits between the hub and the bearing inner. I'm not sure of the dimensions, but it is usually recommended that they be hardened and since you can buy them from regular suppliers I don't know why you'd make them.
I mentioned earlier about using Loctite 35 or modern equivalent on the splines. I see that's only mentioned in the TC manual, but I'm pretty sure it's recommended for earlier cars too. Maybe someone could comment?