Posted earlier in “grinding wish bone” thread that my car has been back in service since this past Sunday.
This is my 1987 XJS that now has vented rear inboard rotors. In addition to having new rear calipers and ceramic pads the front calipers where rebuilt and new pads installed. In order to center the front rotors the caliper shims where moved from their original positions. The car pulls to the right.
All shims at rear on both rotors where replaced as disassembled. Kirby thinks I may have disturbed a shim by the steering arm, but don’t recall seeing any there or would have put it back.
BTW car runs well and the brakes work just fine but have not broken them it to an emergency stop test. Parking brake works better than before.
The single shim in question is intended to compensate for variations in the thickness of the caliper. However, all the Girling calipers seem to be exactly the same thickness, which means all of the shims seem to be exactly the same thickness, about 10 thou IIRC.
The way to check: The steering arm is held in place by one short bolt directly to the upright and one long bolt through the caliper to the upright. Thread both bolts in, then leave the long one several full turns short of seated while tightening down the short bolt securely. Use a feeler to measure the gap between the steering arm and the caliper right next to the long bolt and select a shim (flat washer) of appropriate thickness to fill that gap. If there wasn’t one there before or if the thickness changes, the car will need to be realigned after reassembly.
Thank you for this information Kirbert. Will do exactly as you suggest and will post the findings. Sure hope there is a gap that requires a shim or two as that may be what is causing my steering problem.
Found major gap at both steering arms. Had not paid attention as what shim came out when rebuilding from calipers. Had two 0.033" shims left out and each side took exactly 0.033" shim between steering. Alignment shop not open today but will have it aligned next week. Car steered straight and no pull. Thanks so much for your help.
Excellent! Thanks for the report!
For those that have not followed my adventure of installing vented rear brakes this is a summary of what was done to the brakes. IRS removed from car.New calipers and brakes pads installed on the rear. Rebuilt the front calipers with new pads. My error in not paying attention to what shims came and where when front calipers where removed. Kibert helped me and dangerous steering issue resolved.
Alignment was done today by a local shop that uses a Hunter laser machine. Was very pleased as rear was near perfect so I do not need to do anything back there. The shop provides a print out of reading as received and the final readings.
Front readings to start: Left front camber -1.3 degrees Right front camber -1.2 degrees
Left front caster 3.8 and 3.3 Right front caster 3.3 and 3.8
Left toe -0.48 Right toe -0.23 Total Toe -.073 Steer ahead -0.13
Rear to start: Left Camber -0.5 degrees Right rear camber -0.5 degrees
Rear left Toe 0.02 Degrees Right Toe 0.00 Total Toe 0.02 degrees Thrust angle 0.01 degrees
Final readings for Front after alignment: Toe Left 0.05 degrees Right 0.01 degrees Total toe 0.05 Degrees / Steer ahead 0.02 degrees.
Rear reading as stated above. Very pleased to have it done right.
Thanks again Kirbert for advise about checking steering arm gap to front calipers. A real life saver sir.
I guess the 0.02 degrees Steer ahead was done on purpose to compensate for the 0.01 degrees Thrust angle ?
Aristides
Hate to say it but if you didn’t put the the front and rear suspension pre set tooling in the suspension prior to alignment, you didn’t get an accurate alignment.
I was not aware of the tooling required and had an alignment done without it. Car rode better but not right. Once I discovered that tooling was required I had the the bits made up and and had the car realigned.
Big difference driving on I-95 around DC. Car felt much more planted and controllable.
Gordon
Can you provide the source for the tooling? Thanks.
There is a service shop forty or so miles from here that should have all the tooling to do a correct alignment job, but their prices where very high. Car drives OK for now and seems safe and that is what ws most important at this time. Now on to next XJ-S problem which is A/C.
Home Depot. The specs for fabbing the tools for the front suspension are in the ROM. A design for fabbing the tools for the rear is in my book.
Thanks, time for me to reread your excellent book.