Would anyone happen to know the diameter of the 3 bolts that hold the caliper and the arm together? Or if they are unf or metric? Thank you

 

They should be UNF. I don't know the size. If you can't take the part with you to the store, try taking a measurement for the ballpark diameter and buying the the larger and smaller size in a cheapo bolt. When you discover the correct one, return to the store for the correct grade 8 at the necessary length.

Maybe someone else will chime in with the actual specs.

 

The fixing bolts for the front calipers are METRIC FINE THREAD. They look a bit like UNF but they are not. Usually Manners have them; but if not, most breakers will, or serious bolt places will, and you can drill the ones that need lockwire. If you get really stuck, PM me.
Greg

 

Thank you both. Glad you told me that Greg I was going to run a unf die nut down them to tidy the threads .

 

If you do much work on these cars, or most other cars these days, it worth getting a set of thread gauges.

 

I don't need the size info but I need caliper help! I'm sitting here with grease and dirt all over me, determined to remove my caliper today to either replace it or have rebuilt. I have the easiest bolt out, and starting on the one that goes through the control arm!? Is that correct? And it is necessary to remove, and nothing will spring free on me when it is removed?
Never seen a caliper set-up like this! It's a 1996 model FYI. And the 3rd bolt to me looks like it only holds on the dust shield and bracket for the brake line and speed sensor...so I don't think that bolt is necessary to remove the caliper? Just the 2 bolts that were wired together?

 

You are correct you do not need to remove third bolt only the two wired together!

I just did Mine I have heard stories of washers in between but mine didnt have any? does did yours?

Rusty

 

The bottom calliper fixing bolt (both are metric fine thread by the way) goes though the steering arm, then the calliper and then screws into the upright. The "washers" you mentioned are shim or shims that go between the calliper and the upright, if necessary. These are to ensure the steering arm is not torqued up under bending stresses. If shims come out when you undo the bolt, ensure they go back in. To see if you need shims there, do up the top calliper bolt tight and see with a feeler gauge if there is a small gap between the steering arm and the calliper where the bottom bolt would go through. If there is, make a shim of that thickness, loosen the top bolt, and with great patience and difficulty get the shim in place between the steering arm and the calliper as thread the bottom bolt through the assembly.

 

Greetings to fellow enthusiasts. I am working on a mate's XJ6 and want the rebuild the front calipers but on the last attempt, I bent the 1/2" socket bar. I will probably need to use a 3/4" socket and wonder what size socket to buy.or borrow. Reason for this is that the car is not in my garage, but at his place which is a few miles away.. Any information will be gratefully received.

 

Hi Asch

Don't waste your Time or Your Money with another Socket and or a Socket Bar, as having done this job myself on all of my Cars, you could easily spend a Week on getting nowhere

Because what often happens is that the actual Shaft of the Bolt can get seized in the Caliper at which point you may be Tempted to try a bit of heat and when you find that doesn't work, extend your Socket Bar with a 4ft Scaffold Pole like I did

At which point then you might end up by Shearing the Head off the Bolt and after you've tried to drill that out, then you may have no choice other than to cut the Steering Arm off 'been there done that don't want to do that again!)



Instead go and buy yourself a Mains Powered Impact Wrench, which I got off ebay for about £35 which could be the best £35 that you have ever Spent in your whole life!

You can see how I struggled with this on Pages: 10 and 11 of my 'Cherry Blossom' Restoration Thread, including trying to do this with a 4 ft Scaffold Pole on the end of a Socket Bar

And then you can see a Video of my Mains Powered Impact Wrench in Action!

Removing among other things a Solidly Rusted Wheel Nut on a Land Rover as well as the Caliper on my XJS which only took me just a couple of Minutes and the Impact Wrench even comes with its own set of Impact Sockets

Which is worth the price of Admission all on their own!

Buying one of these is a 'No Brainer' I've just lost count of the number of times I've used it for all sorts of Jobs

Have a look at my Video and then decide for yourself

Mains Powered Impact Wrench in Action removing the Caliper Bolts on my XJS

 

Thank you for your interesting reply which I will make the fullest use. Thanks.

 

M12 x 1.25

I have just cleaned my threads and also bought a pair of new non-original bolts, and it is definitively M12 x 1.25

 

I already have a pneumatic 1/2" impact windy spanner (not a Lidl one I hasten to add) Are the bolts a close fit? I will have to take a portable compressor with me. I suppose that 12 mm means a 19 or 18mm head. Can you tell me the length as I would like to replace them with new.

 

19mm head, at least in 1977. Later bolt could in theory have 18mm hex I guess

I do not have the lengths for other than the bolt attaching the steering arm to the upright. This is 35mm long. The caliper bolts are longer, my guess is 40-45 and 60-65mm

Leo

 

Hi Asch

Unless you have a very big Compressor, then once again I think you'll be wasting your time

As unlike an Air Impact Wrench, the Electric Impact Wrench never falls off with the Torque that it delivers