Vargas wheel cylinder too small for backing plate?

[Jim Ed]

Hello!
I have a 1973 non Super Beetle.
I recently purchased front and rear Brazilian wheel cylinders made by Vargas TRW.
Yesterday I installed the left front wheel cylinder.
The big hole in the front backing plate that the wheel cylinder goes into is a little too big for the Vargas wheel cylinder.

I installed the new Vargas wheel cylinder and there was some play there but, after I tightened the wheel cylinder bolt, installed the shoes, and springs, the wheel cylinder is tight without any play.
Will this be acceptable or should I get a set of German made wheel cylinders and or new backing plates?
Thanks In Advance!

Update: I measured the cylindrical protrusion on the old wheel cylinder and compared it to the new wheel cylinder. They both measure about 1 1/32 Inch D.
I guess somewhere along it's 40 year trip, someone must have enlarged those backing plate holes.
I guess I need new backing plates.
Are there any special tips on installing them?
I think the backing plate bolts get 36 ft. lbs.
I am planning on applying PB Blaster to those bolts up to a day ahead of time.
Do they need a gasket or RTV sealant applied between the backing plate and the knuckle?
TIA!

[Marc]

I wouldn't lose any sleep over this. Think "mind over matter"....if you don't mind, it don't matter. Seriously, just let the wheel cylinder swing as far forward, in the direction it would be pushed by the rear shoe, before tightening the bolt. The amount of misalignment will be trivial and shouldn't cause any loss of performance.
If it bothers you, go ahead and round up some "tighter" backing plates (any Type I from `68-up will fit) and replace them if/when you service the rear wheel bearings.

[Jim Ed]

Seriously, just let the wheel cylinder swing as far forward, in the direction it would be pushed by the rear shoe, before tightening the bolt. The amount of misalignment will be trivial and shouldn't cause any loss of performance.

But what about the front shoes? They are mounted sideways. There is no rear shoe or would the bottom shoe count as the rear shoe?
If what has worked works without any problems, mount the left side proportionately to the right side. In other words, look at the right side that you have not disassembled yet. Notice how the cylinder has been installed. Install the left side in like manner.

[Marc]

...But what about the front shoes? They are mounted sideways. There is no rear shoe or would the bottom shoe count as the rear shoe?...

Sure, for the purposes of this discussion.

What I'm saying is that the wheel cylinder will be pushed in the direction of wheel rotation when the brakes are applied until it bangs against the round hole in the backing plate. Even if you don't preemptively position it that way it could happen the first time you big-leg the pedal; after that it should stay put, at least until the first time you do a panic stop while backing up at high speed (hopefully that's not a regular occurrence).
The worst thing that's likely to happen with "oversize" backing-plate holes is that the wheel cylinders could eventually work loose, in which case you'd hear a mysterious little click/clunk when braking for the first time after a change in travel direction. It'd have to go on for a very long time before there'd be any danger of the brakes failing, even if the bolt were to fall completely out the odds are that the brakes would still function.

Believe it or not, I've seen shoe frames which were bent over from He-Man pedal application, so I don't care how hard you tighten that little m8x1.25 wheel cylinder bolt it's not going to be able to hold the W/C from shifting on hard braking - but because of the elegantly simple design used, it isn't going to move enough to cause a loss of function.

A "trick" that can be used to extend the life of a worn backing plate, or a worn bearing bore in a rear control arm (or swingaxle tube) is to wrap a narrow strip cut from a feeler gauge around the O.D. of the W/C snout or wheel bearing. I'm not encouraging you to attempt this, it just seemed like a good place to bring it up.

[Jim Ed]

Hello!
I have a 1973 non Super Beetle.
I recently purchased front and rear Brazilian wheel cylinders made by Vargas TRW.
Yesterday I installed the left front wheel cylinder.
The big hole in the front backing plate that the wheel cylinder goes into is a little too big for the Vargas wheel cylinder.

Update:
I received the 2 backing plates that I ordered from CB Performance.
The big hole in this front backing plate that the wheel cylinder goes into is very close to the same size as the cylindrical protrusion on the wheel cylinder. I can see that it is going to be a good fit with no play.