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MG TD TF 1500 - TD/TD Rear brake puzzle

Having restored many T series cars over the years, I now find an item I have never noticed before and would welcome any observations the members of this list may care to add.

Today I was attempting to fit new rear brake wheel cylinders to a TF axle's back plates and was having a hard time getting them to sit correctly in the cut out slots. They just would not go in.

Upon closer examination, I noticed that, (apparently), spot welded to the inside of the back plate, there appeared to be a thin metal shim, about the same size and shape of the cylinder's rear face, which was bowed outwards, away from the back plate, in such a way as to make the cylinder stand proud of the inside face of the back plate. The old brake cylinders, which had been removed, would fit and seat correctly, but the replacements, (which appear to have a slightly larger diameter barrel, incidently) just would not go through the slot and seat themselves in the proper manner.

I have never seen (noticed) these "shims" before and can only presume they are there to allow the brake cylinder to move (slide) with less friction. That is, if you can get the cylinder to fit properly.

Need I now grind off these shims to allow the new cylinders to fit?

Any comments, anyone?
G.E. Love

I altered the new cylinders to fit on the slides. One was 'tighter' than the others. Must have worked, because my braking seems to be good on the new system.

I hope this helps,
dave
Dave Braun

That's what I shall have to do as well. My interest mainly lay in the fact I had never encountered slides before.

When you say "on the new system" was there an old one? Perhaps one that didn't have slides?
G.E. Love

I have seen them before, as well as had to file the new rear cylinders. George
George Butz

Nope, I meant on my NEW brake system, when I did the complete rebuild.

The slides could easily have been overlooked in the past, if they were the typical rusty brown color that brake components seem to achieve in use. They would only become apparent when the assembly doesn't go as planned. In my case, one rear wheel cylinder 'stuck' in the through plate more than the other. That's when I made shure both cylinders would 'slide'.

warmly,
dave
Dave Braun

Ok, thanks. That seems to make it all clearer.

I have to say I had never noticed these devices before. The back plates on this car were, as is my wont, sandblasted and painted before being refitted and it was only when I found it impossible to install the brake cylinders easily did I then notice these "shims" for the first time ever.

Who said "There are none so blind as won't see"?
G.E. Love

Dave B from your comment "altered the new cylinders to fit on the slides" I infer that you filed/shaved down the the tangs on the cylinder versus the shim on the backing plate. The reason I ask is the Bud K recently helped me go over my brakes recently and on the right rear ,the tab holding the brake cylinder onto the plate broke off and the cylinder shifted outward ( cylinder actually abraded down from contact with the brake drum) My question is would it be more secure to file down the shim leaving the tab full thickness for strength . I ask having recently survived total brake failure contributed to by tab of the cylinder breaking off causing rear brake failure.


Jon Levine

Jon, I recall only filing the edge of the casting a bit, likely less than a eigth of an inch in length only. I think the casting was just sloppy or not machined correctly. This minor filing doesn't weaken it at all. The backing plate holes over the years have never changed size- just the sloppy new or reproduction cylinders. George
George Butz

Jon,

I concur with George. I was installing "new" rear cylinders, and had to increase the space in front of the tang on thy cylinder. Still plenty of meat there ofter filing.

Your failure was likely one of long time wear.

hope this helps,
dave
Dave Braun

This thread was discussed between 29/08/2008 and 31/08/2008

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