need help with some dimensions

[1965mt]

I have. '67 swing axle that I replaced the brakes with discs. Has anyone measured the stock backing plate thickness? it is a little higher than the oring seat on mine.
Also, has anyone measured the oring cross section? mine is 2.5mm but 3mm would seem better?

[Ol'fogasaurus]

A '67 is a short axle while the '68 swing axle and takes the same setup as a IRS from '69 and on. Which kit did you order?

Lee

[1965mt]

it is the empi kit, seems ok

[Ol'fogasaurus]

On my black buggy build I took pictures of my putting discs on. I did have a problem with one bracket being miss-drilled which, with help from who I bought the kit from, I got the problem resolved.

There is a definite difference between the long and short axle disc brake conversion but I don't know if the caliper mounting bracket would be included in the difference.

Lee

Spell check screwed up again!

[Marc]

The depth of the bore in the end of the axle tube relative to the flange where the backing plate/bearing cover or conversion-kit caliper bracket seats is different between pre`67, `67 Beetle, and `67/`68 'Ghia/`68 Beetle/Type III - so there is potential for the caliper not being centered on the rotor if the conversion kit is not designed specifically for the axle tube being used.
One must also never mix & match bearing covers and axle tubes. Since all use the same wheel bearing, the tubes with the shallower recess must use covers with correspondingly deeper recesses and vice-versa. If the wrong combination is used the bearing (and axle) will have end float - or the backing plate won't be pinched correctly between the flange and the cover, allowing it to knock about on the bolts.

[1965mt]

I just bought new tubes and matching covers. These have the 13mm bearing depth. I just bolted the cover, the gasket, and the plate to the tube and measured 20.75mm space between the bearing surfaces. I assume this should be closer to the 18.96mm that the bearing itself measures.
My backing plate that came with the disc brakes is 6mm thick. This tells me that a stock backing plate is in the ballpark of 4.7mm to 5mm.

[1965mt]

http://images.thesamba.com/vw/gallery/pix/1534672.jpg

[Marc]

I'll measure some backing plates & stock axle tubes tomorrow but I agree with your findings, the nominal thickness of the bearing is 19mm and the parts should stack up to just accommodate it.

You may have to resort to having some machining done. Might be easier to mill the caps than the conversion backing plates.

You should be able to get away without the gaskets if the O-rings are doing their job, but that'd only improve the situation by ~.010". The `68 (also Type III) covers are 3mm shallower, so they'd be no help either.

[1965mt]

thanks, that would be helpful

[Marc]

Just measured a half-dozen or so backing plates - most were ~.215" (thinnest was ~.210", thickest ~.230") so it looks like the nominal dimension is about 5½mm.

[1965mt]

that is interesting. thank you.
any value over 4.7mm is room for the bearing to move. its not what I expected.