Brake shoes, drums, levers and spreaders, adjustment and issues with new parts

Some more comparisons, how relevant, I don't know.

As mentioned above, lever arm about 1cm longer so fouling return spring.

Shape of lever arm is otherwise similar, see pic of old ontop of new.


Next comparison. The shoes are similar except for the holes where the top Spring sits. These are very different, with the new shoe holes closer to the outer edge of the shoes. (Measured accurately, and caliper then moved to show measurement). The old and new springs are the same size meaning the old shoes have less pressure on them at the top. This could explain why the shoes are riding up towards the cylinder after using foot brake to adjust.



Confused, yes I am. Will @Zed's welding work, probably, but I'd rather know what the issue is before I go down that route. I have time, so it's not a problem that needs to be rushed.

 

I've had a cup of tea and formulated a plan of action.

Meet up with @mcswiggs next week at the Menshed and look at his brakes to see what normal looks like as his is a similar aged bay. Whilst I'm at the shed, use the proper welder there to weld up the spacerbar as suggested by @Zed.

In the interim I'm going to speak to Alan Schofield about parts, especially the lever arm which is definitely wrong and the position of the spring holes in the brakeshoe which may be immaterial.

 

From the same supplier but probably not from the same manufacturer.

IMO the gap at the end of the spreader bar is too big possibly because the slave cylinder pistons have not retracted far enough. The trailing (rear) shoe is adjusted too far out and the leading shoe not far enough. If you can get the top of the shoes closer together it will reduce the spreader bar gap, then adjust both shoes the same amount. If you can’t get the pistons to retract further then zeds weld to reduce the gap should work, but I’d only do that if I really had to.

The handbrake works both shoes via the spreader bar.

 

Thanks. I adjusted the shoes earlier after what was said so that the star adjusters were about the same. and then took it all apart without a photo..Doh. anyway, these are the shoes held in place manually to show the piston position.

 

Heres a couple pics of mine the first is ,i think a photo before i did any work , the second shows the arm that the cable hooks into hitting the bearing housing thus stopping the cable from being pulled further and then engaging the brake shoes with the drums , well almost shows it its just out of sight but shows where to look and perhaps listen

 

This photo shows how close the lever got to the retaining spring ,as i recall if i added more weld the arm would have contacted the retaining spring.
I may be wrong , i generally am , but without the retaining spring the shoes tend to buckle about under the tension of the long springs and the pulling of the handbrake lever , i know its been said that some models dont have them but certainly mine needs the retaining springs ( mines a 73 model)

 

Here's a thing Chris - humour me and see what the pistons do if you open the bleed nipple. Like Sproggy I'm having to cast my mind back 10-20 years and have a thought that they sometimes do not fully retract. Vague I know and I can't recall why either, but I do remember doing that once for some reason.

 

@Sproggy4830 thanks for the photos. Yes the hub would do that. My backplate do not have the holes for the central spring which I believe was deleted by VW before my '78 model.

@Zed, humour is the only thing not throwing my toys out of the proverbial pram. Quick question. If I slightly open the bleed nipple whilst squeezing the pistons in (ooh err), will I avoid getting air into the system. I'd rather not have to bleed the system again.

I'm going to try first with my old cylinders to see how far they go back in.

 

IIRC when I did this the top spring did the squeezing. Now, that what it should do without opening the nipple but for some reason it didn't. Maybe after that I replaced the flexi blaming that but honestly I only remember some sort of enlightenment had by opening the bleed nipple. Can't see air getting in, some people bleed their brakes by opening them all and going to bed.

 

Because the brake master piston uncovers the inlet port from the reservoir at rest, squeezing brake cylinders just results in the fluid going slowly back into the reservoir through a small hole.

The spring at the top of the shoes should be pulling so hard against the piston that it closes up until the brake shoes themselves are resting on the spacer, regardless of what the handbrake lever is doing, so the pistons should already be no longer holding the shoes apart.

However it looks to me like the pistons are fully "in" in the picture, the shoes are just not quite touching the dust seals - maybe what you have is the wrong slave cylinder one side, and wear and tear exposed this, then the obvious differences between the replacement parts and original just emphasise the difference.

Measure the "at rest" spacing between the ends of the pistons both sides..

As an aside the last time I replaced the rear brake shoes on mine, I had to reuse the handbrake levers as the brake shoes did not come with the levers unlike some I bought in the past.

 

@mikedjames , both brake cylinders were changed at the same time, but I'll measure the gap between the brake ends and the dust cap. I have always assumed there should be a small gap there so that the dust cap is not worn down by the brake end touching it each time, but I've never really thought about how small this should be?

 

Just to add to my general enthusiasm for this 'easy' job, I noticed yesterday that one of my CV boots has split after less than 3000 miles....

 

That seems to be about the norm now for the rubbish rubber quality available.
I've had these on for well over 2 years and they still seem to be holding up so they could be worth a go: https://www.ebay.co.uk/itm/140244537672

 

Its so annoying that the good VW CV boots that Heritage were selling a few years back have vanished..
I got so annoyed with boots lasting between 2 years and 3 months from the same brand, I splashed out £140 about five years ago just for four VW branded boots.. so far so good... probably saving money now at the rate I was swapping boots before..

 

To humour @Zed I've measured and slightly bled my cylinder. As I've taken the brakes apart yesterday, it gave me lots of room and to apply pressure, I put a clamp across the cylinder, carefully opened the bleed valve and with added pressure via th clamp on the cylinder, no resultant movement.

The new cylinders are 92mm end to end when fully compressed, leaving a mm or two gap between the brake shoe and the dust cap. My old cylinder closed to 92.8mm.

 

Meaning that if you had fitted the new shoes with the old cylinders the gap at the spreader bar would have been even larger.

 

Ah well, was worth a go just to check.

 

There was some complaining on the samba a while ago that t25 shoes were being sold as late bay shoes and there were enough differences to cause problems.

I don’t know if that’s your problem but I thought it was worth a mention

 

@77 Westy yes, but I've now fitted my old spreader bar and new shoes, cylinders etc and the gap is minimal and it looks like it might work.

Whilst I was messing around with @Zed's suggestion (which is still useful knowledge even if it wasn't material) I noticed that the issue with the spreader bar is not with its overall length but with the depth of the slots. Possible not as originally thought but because of the slot inner arm length of the spreaderbar slot which goes over the handbrake lever and engages on the shoe slot. On mine, it is resting on the shoe slot end before the base of the spreader bar slot engages with the handbrake.

Picture below is mock up with old bits to show what I mean.