403 front suspension bottom bracket shims

mikebro · #1 (**permalink**) 09-09-20, 12:27 PM

Long story - got all the front suspension components back from machining - remetalled and machined kingpins and top and bottom swivels, with new bushes pressed in and reamed. All good. Oh, and the transverse leaf spring has been rebuilt with all steps removed, and two leaves replaced including the main, bottom leaf with the bottom bracket eyes.

Started putting it all back together. With spring installed and top swivels installed so that the two hubs are both hanging down to fit the bottom swivel pins, there is a gap both front and rear. The safety strap fits in the front gap, with a similar width spacer for the rear gap. There is now (both sides) a few 10's of thou space both front and rear (very similar both sides).

Now - the Service Manual says to add shims in the rear gap only. In my case, to avoid stressing the swivels, it would make more sense to add shims front and back, unless I'm missing something.

I suppose my question, bearing in mind that the new spring may not be exactly the same width as original, is whether it is part of the design that some stress is put on the swivels - or should I go with my gut, and shim front and back?

Hopefully someone on this forum has done this job and can answer the above?

I want to get this right, after all this work.

Cheers

Mike
403-1402

Geoff Dowdle · #2 (**permalink**) 10-09-20, 08:37 AM

Mike ,
Try some feeler gauges to measure the gap front & rear .
I would not recommend to fit thin shims , Say .020 thick as they will probably break up over time .
I suggest the safety link is built up and machined to the exact size and the other side a new thicker shim made.
A bit of work but I assume you don't want to do it again in a few years.

Geoff

mikebro · #3 (**permalink**) 10-09-20, 06:02 PM

Quote:

Originally Posted by Geoff Dowdle

Mike ,
Try some feeler gauges to measure the gap front & rear .
I would not recommend to fit thin shims , Say .020 thick as they will probably break up over time .
I suggest the safety link is built up and machined to the exact size and the other side a new thicker shim made.
A bit of work but I assume you don't want to do it again in a few years.

Geoff

Thanks Geoff

Great advice - much appreciated. As you say, more work but worth it.

Mike