Issue 18 stepped bearing

[john.p.clegg]

Dear All

Am beginning to panic,need the car for a charity run this weekend and have just rebuilt the rear end...after looking through the manual decided that the step of the inner race of the inner bearing should be facing away from the spider...am now having problems fitting the brake slave cylinders...have I got the step the wrong way around??

John

Edit:- have the manual in front of me now and Section G,Page 6,Fig 5,certainly looks like the step is away from the spider (towards the wheel)...

[john.p.clegg]

Panic over!!! just stripped the callipers off and cleaned up the mating surfaces and just slipped back in....like nothing had happened...10 thou of run-out on the left-hand side and 24 thou run out on the right hand side....now to re-connect the brake lines/linkages,adjust/bleed/torque and off for a trial run......had been a knackered driveshaft (thought it was the bearing) on the right-hand side

John

[andyelan]

Hi John

That run-out looks a lot, esp. 24 thou on the RHS

Regards
Andy

[69S4]

10 thou of run-out on the left-hand side and 24 thou run out on the right hand side....

John

You'll struggle to keep the handbrake working with that amount of run-out - especially the RHS figure. That's a spark plug gap! Do you notice any pulsing or longer than normal travel, in the brake pedal?

[john.p.clegg]

....according to the book one is allowed 40 thou....

John

[69S4]

....according to the book one is allowed 40 thou....

John

Where did you get that figure from? My workshop manual says .004 (four thou) runout, with the handbrake pads having a maximum gap of .003 each side of the disc

[john.p.clegg]

Bugger,have I misread again...will double check and then it's time to get the shims out,but the test drive (ten miles) looks promising..

John

P.S.
any advice on shimming the spider/disc?

[andyhodg]

John

I machined the mating faces of the spider in a lathe to correct my problem with runout. I trued up both the face that locates the disc and that that goes to the (in my case) the CV joint (or doughnut).

My runout was just within spec but I was trying to improve it as I appear to be getting pad knockback, i.e. a long brake pedal but on the second application it is short. It is not something that bleeding will solve, that was my first try. Still not solved the problem??

Regards

Andy

[john.p.clegg]

Andy (et Al)

Have just spent the past week renewing the rear end (uprights) but the spider wouldn't fit in my small lathe ...also there is disc run-out to consider on top of spider run-out..will attempt shimming next week...watch this space...

P.S. did you improve it?

John

[alexblack13]

Hi All/ John,

Shimming the discs true is a real fiddly job John. Nightmare to be precise! Why can't you get the drive shafts into the lathe?

If you do manage it remember to machine both surfaces very carefully. And (forgive if I'm teaching gran to suck eggs here) Make sure the shaft is trued in the lathe to +/- FA..... Zero run out prior to machining. I also had to machine off the ''fail-safe'' stub.... and center drill the remaining faced off shaft. Rotating center must be good too. True the shaft on the bearing lands. When done you should have less than 004'' I got almost nil on one side and 0015 on the other. Result? good pedal with no excess movement...

Keep at it mate.

AB.....

[alexblack13]

Hey John.

Meant to say if you want them done (after the weekend) send them or bring them up. We can do them and you can set off back same day. Or... ACCOM' if you need it...

Cost?? Nil...

Alex B....

[andyelan]

Hi John

I find shimming the discs strightforward enough although describing the correct technique for doing it is a bit trickky. I'll have a go though.

1) Without the disc, clock up the spider to determine which leg is the highest. This becomes the datum ie the one which will not require any shims. Mark this a "A"

2) Mark the other legs "B" and "C" working in a clockwise direction

3) Fit the disc

4) Mark the disc at "12 o'clock" "3 o'clock" "6 o'clock" and "9 o'clock"

5) Now add an equal thickness of shims under legs "B" and "C" untill the disc runs true at "12 o'clock" and "6 o'clock" (don't forget that the OD of the disc is about 2.5 time that of the spider so the shims required will be 2.5 times less than the discs indicated run out)

6) Finally re-distribute the shims under legs "B" and "C", in equal amounts (ie if you remove 10 thou from under "C", 10 thou must be added under "B") untill the disc runs true at the "3 o'colck" and "9 o'clock" positions.

7) The disc should now run true all the way round.

I know it's a little long winded to describe but to do the job is fairly strightforward, you might just need a couple of goes at it. Also don't get too hung up on getting eveything perfect, if its better than 5 or 6 thou I doubt you'll have a problem

Regards
Andy

[john.p.clegg]

Thanks Andy

Sounds very much like shimming the steering rack....

John

P.S.

If only the spider had four legs...

[john.p.clegg]

Well,not one to sit around doing nothing if anything needs doing,back under the car....only shimsteel I could get is 0.004"....and after an hour and two have come up with some better figures....reduced the right hand side from 0.024" to 0.006" and the left hand side from 0.010 to 0.005",should produce better braking and handbrake operation.....

John

P.S.
I now have plenty of 0.004" shim strip if anyone needs any..

P.P.S.
Does anyone know where I can get 0.001" and 0.002" shimsteel from?

[andyelan]

Hi John

Try Chronos

www.chronos.ltd.uk

Regards
Andy