Hi all!

Just joined up, and looking forward to participating. Probably like more than a few members, I've finally been prompted to join by a small difficultly with the Cat. Fortunately this one is pretty minor:

I'm currently replacing the rotors on a '94 XJS. Everything's going mostly smoothly so far, got the bearings re-packed, took my time with the end float, almost have one side done. But...

Is there some trick to getting the shims between the steering arm and the caliper back in?! I've been at it for hours now, and cannot get them back. I did figure out that you have to loosen the other steering arm bolt a little, which at least gave me some room, but I cannot get everything to a position where it lines up.

I have the top caliper bolt inserted, and have been holding the shims in place agains the bottom caliper bolt hole while I try to swing it into place. That seems like the most promising technique so far, but maybe I'm missing something obvious.

Would love a few tips from the folks who have done this. Cheers,

cf

 

Welcome to the world of FUN.

I use a "magnet on a stick", with the arm in place, the top bolt loose, and dangle them into place whilst sliding the lower bolt in, and with the 3rd hand shove the calliper into synch.

The intake of JD prior to this adventure, always makes it soooo much easier.

The first few I did really tested the brain cells, but after 6 or so, it kind of fell into place.

The current Jags dont have those shims, whoopee.

 

Hi CF

Fitting those Shims can be a real PIA!

So this is the way that I do it.

(1) Bolt the Arm on just tight enough to measure the gap for the Shims.

(2) Decide how many Shims you are going to need.

(3) Take the Arm right off and then put the Bolt that holds the Shims on First, together of course with the number of Shims you require.

This makes the Job dead easy, as once you have that Bolt in place together with the Shims, they can't fall out.

Then just put in the rest of the Bolts and Torque them up according to the Manual.

I have struggled for hours like you did, until I discovered this way.

 

Brilliant, OB, just what I need for tomorrow or the next day!
Greg

 

Cheers Greg! (Lol)

No doubt your Impact Wrench will be pressed into action.

 

Just did this last weekend, and I did it exactly as OB details.

The other hint I'll give you is I have a bottle jack that is very skinny and often comes into use in unexpected ways. I used it to give the caliber a place to rest at the right height and to act as that third hand Grant mentions above. The caliber is surprisingly heavy, and the bottle jack made it easier to get in the right spot to get the bolts lined up.

 

Not sure that I want to ask Grant what he used as a third hand , but does it look like a bottle jack .

 

You been looking over the fence again HAHAHA.

I'm on the wagon now, and I have never needed to do those shims since.

 

The easiest way is to NOT REMOVE the caliper. Remove the bolts to the hub from behind with a 'flex-socket' and pull the hub. Slide the rotor out and slide the new one in!!!

Reassemble.

bob

 

nice idea, them durn Texan's always gotta way.

here's one, latest survey says some texas people have the longest legs in the world! song,"that long tall Texan"

wonder why??

 

WHERE were you last week???

Now you tell me!

 

I made the mistake of removing the caliper back in the 1980s and the shims fell out. I had to have the car aligned (set toe) after reassembling. My buddy that worked with me at the jag shop came over and told me to NOT pull the caliper and just remove the bolts from inside the rotor.

Lesson learned!!!!!!!!!!!!

bob

 

Thanks for all the replies, I feel much better now about taking so much time over this one!

I managed to get around to finishing off the first side and doing the second this past weekend. I used a combination of Grant's and OB's techniques, which worked pretty well.

(1) Insert top caliper bolt.
(2) I ended up not completely removing the steering arm, but I did slacken off the top steering arm bolt much more than I had initially, at least three full turns. This gives about a centimeter to play with between the steering arm and the caliper at the bottom.
(3) The caliper wants to fall towards the steering arm and close up the gap, I kept it out of the way by wedging a screwdriver between the near side of the caliper and the brake disc.
(4) I used a pair of cross locking tweezers with angled ends to hold the shims together and suspend them in front of the steering arm from below. I then slid the bolt through the shims. With a big enough gap, you can look down from above, see the end of the bolt protruding into the gap, and it's not too hard then to get the shims over the end.
(5) With the top steering arm bolt loose, the steering arm wants to rotate down. I removed the screwdriver holding the caliper and slightly rotated the both the steering arm and the caliper up until both holes aligned and I could get the bolt through. This is also a little fiddly, but less so than the shims.
(6) More wiggling up and down until the bolt finally finds the hub carrier.

Unfortunately, however, I think there's going to be a repeat performance. When I measured the runout on the first side, it was 2 thou. On the second side I get 0.010". Rotors are EBC, checked at the factory to be within 0.002", so I doubt they're at fault. I also cleaned the hub really well.

I think my options are (a) get shims for the rotor, or (b) have the rotor turned on the car. Any thoughts?

Thanks again,

cf

 

The runout is 10 thou, right?
Before removing the disc from the hub mark the disc/hub postion with a chalk line.
Remove the hub, remove the disc from it, and scrape the hub mating surface carefully with a sharp bladed chisel, particularly the very short (about 4 mm) upright part of the hub that is the hubcentric part for the disc's location. Spray loads of brake cleaner over the cleaned surfaces.
Then fit the disc 180 degrees from the mark on the hub, and try again. Three goes is not uncommon, do not despair!
Greg

 

Thanks Greg!

Yes, the runout is 10 thou. While I did clean the flat mating surfaces of the hub with a wire brush, I did not particularly pay attention to that inner lip which the brake rotor centers on (I assume that's what you mean by the 4mm upright part). It does make sense that there could be some rust, etc, in there which was not covered by the old rotor and is preventing the new one from sitting perfectly flush.

I will have at it with a chisel. With any luck that will, combined with indexing the rotor, get me there.

Cheers,

cf