Because my cousin and I both own jags, we have decided to "partner up" when doing repairs. His XJS and my XJ6 are essentially the same when it comes to the rearend assembly. Sooooo... we decided to tackle a total rebuild of his brakes with the understanding that mine are going in next spring. Here are some highlights (yes it was successful in the end):

1. The total time was about 8 hours with two people, a lift, lots of tools and about 4-5 beers each.
2. Dropping the rear end out of the car is a certainty. Placing it on a work bench (or rolling cart in our case) makes access easy.
3. Plan on buying new seals for the calipers and new diff seals too. We replaced all these while everything was apart.
4. It is much easier to access the calipers (even with the rear end on a bench) by taking off the wishbones and outer wheel hubs. This is not a difficult job but make sure you keep all the threaded rods, brackets, washers and nuts together, they can easily get mixed up. Take pics if you have to. This is also a great time to clean these parts up in a bucket of gasoline or with a wire wheel.
5. Replacing the caliper seals and pads is so easy, anyone can do it.
6. You may have issues with the break lines that attach to the calipers being rusty to the point of breaking them. Plan on replacing them, if you dont have to then you are lucky. Pre plan by hitting them with (insert your favorite rust killer here) seveal times before the job begins.
7. It sure feels good when the job is done knowing you saved at least 1k in labor. Maybe more.
8. Buy a thin 5/8 wrench that ratchets and pivots on the end. This will cut 30 mins off your time to extract the bolts that hold the calipers on.
9. Measure the thickness of your new rotors vs the old rotors to see if they are the same thickness. If they are not, shims may have to be added/deleted. We did not have to do this because our rotors were only .005 different and the smallest shims are .010. There are shims on both sides of the rotors...make sure you do not mix them up.

If anyone is thinking about doing this job, feel free to email me. Im sure others have done this job and it is always nice to know you have someone to ask questions before you begin.

Good Luck!!

 

Good job! I need to do this. Previous owner replaced the calipers, but left the old rotors. Same with the front, but I already replaced those rotors. The rears are all pitted and look worn out. They are the sandwich type rotors, and the wear surfaces appear thin.

Someday I will get to this, but the car is on jack stands in a one car garage, so not enough room to drop the cage and get it out unless I raise the car even further. Hmmm.

 

Having a lift and lots of work space really helps. Also, those sandwich style rotors (from what I hear) are not good. We found some solid ones. They look much better for sure.

 

I've got my pads and rotors waiting to go in now and will be sure and pick up the seals as well. Since my shop is my driveway I'll be waiting till the spring to tackle this one. I would have loved to see a write up with pics as this is on my list of projects. Did you find links to good info before you started the job?

Other than the brake lines and the 5/8" wrench was there anything else you would have liked to known before you started the project?

 

Well we didnt really look at anything specific before hand. Just started in and it was pretty self apparent on what to do. The only "tricky" part was replacing the diff seals. Its not hard but you have to disassemble and reassemble everything carefully. Removing the old seal takes patients and it helps to have many diameter tapping blocks available along with a good vice. Other than that, just remember to keep all the threaded rods, washers and nuts together. Maybe take a picture so you know what it looks like. We had the advantage of having a fully assembled rear end that we took off a parts car to use as a model but that is not necessary.

Yeah I know pics would have been nice but it was a dirty job (hey mike rowe) and it would have slowed us down. I am doing this again in the spring on my car. I can already see one of the caliper seals is bad along with one rotor. I will try to take pics during that job and post them.

By all means, if you get stuck then email or post on the board and I can try to help you through it.

 

Well I am about ready to tackle this brake job on my car in about 10 days. Although my cousin is no longer here to help me, I have found a couple suitable replacements and a local mechanic shop that is willing to let me use a bay/lift on a saturday for $40.

I will be replacing my rubber brake hoses along with the rotors, rebuild the calipers, pads, and diff seals. Replacing fluid as well. One of my calipers has blown a seal and the pad is pushed against the rotor to the point of a metallic sound. Car stops fine but sounds awful.

Hopefully I can get some good pics of the process to post when I am done. This is a good 6-8 hour project and I am crossing my fingers that all goes well. Wish me luck.

 

Can't wait to see the pics and write up.

 

The rear brake job is now complete. Total time from start to finish was about 10 hours. We did not replace the diff seals, let well enough alone as they were not leaking. The calipers were in bad shape and it took some effort to remove the pistons and rebuild them. There really wasn't anything overly difficult, it is just time consuming. Keep in mind there is part of the exhaust that will have to come off with the rear end and it cannot be taken out until the calipers are removed. You then have to replace that section once the new rotors are on before the calipers are re-installed.

The one time ******* we ran into was re-installing the park brakes. My suggestion would be to make sure you wire wheel the mating surfaces before putting the pieces back in and remember you may have to use the leaver arms to ensure the pads are square to the rotor which lines up the pins/screws that hold the mechanism on the caliper.

I have a few pics but not many, it is not easy to photograph while working on this long project. I will post them on Monday. If anyone wants more information about doing this project themselves and saving about 1500 in labor, just contact me.

 

Resurrecting this thread as I need to jump on this soon. I am hoping you are still on the forum (or for someone else to chime in). While doing some preventative checks on the car I noticed my diff was leaking some and it's time to refurb the brakes.

Can you give us some more details on what is required to drop the IRS assembly? I don't have a lift so it's me, some jack stands and a jack. This is the part I am most nervous about since I have not done it before.

Also, can you give some more details on what you did with the park brake assembly? That is something else I want to fix while I am in there since it doesn't work today.

Thanks,

Eric

 

Change all the hoses (3) at the same time. It make a big difference. done
this three times now and if you can get the whole rear of the IRS 18" or higher - you can pull the IRS out easily without wheels. Be sure the car is held up properly!

The hardest part is getting your exhaust connections loose - rust remover first the the day before or use your Saws All.

I have a square piece of plywood that fits under the center or the IRS.

Rebuilding the E-brakes is a matter of taking them all apart, cleaning and'lubing them and watching the ratchet mechanism work. Be sure to use quality E- brake pads as the cheap one will break and you get to do this all over again.

Remove all the old brake fluid, clean out the lines and start over from the RR, LR,RF and then LF when bleeding. It takes time unless you have a GOOD power bleeder.

 

+1 on everything Roger mentioned. I'll just add a few bits.

IRs removal, in a nutshell, isn't all that hard.
-Disconnect driveshaft
-Disconnect exhaust (grrrr!)
-Disconnect park brake cable
-Disconnect brake pipes
-Disconnect radius arms at body (big prybar needed)
-Disconnect 4 "vee mounts"
-Lower away!

You'll want a good floor jack. Or even two good floor jacks. A pair of helping hands is...helpful.

Reinstalling is a little awkward as the IRS is very front heavy. I have a method of "walking up" the IRS which might be helpful, if your're interested.

On the parking brakes: reattaching the cable to the lever arms can be tricky. As I recall (a little foggy here) it's best to attach the cable and *then* ratchet the lever arms for your initial parking brake adjustment. If you ratchet the lever arms first, you'll have problems getting the cable on. Maybe Roger can clarify/verify, if his memory is better than mine :-)

Also, the parking brakes require "bedding in" to work properly, just like regular brakes pads. We can get to that, if you're interested.

Cheers
DD

 

Thanks for the feedback guys.

Roger, Any information/dimensions you can give me on your piece of plywood for the rear end? Does it help with the front heavy nature that Doug refers to?

Doug, Of course I am interested. Please expand further on the walking up method, bedding in process and any other details you are willing to type about. Knowledge is power, and it helps me visualize and feel more confident when I actually start turning a wrench.

Thanks again,

Eric

 

Board is 3/4 ply, 13 X 17". I lust lift the whole thing upward and start
attaching the (4) V mounts. Leave the bolts loose until you have the
thing in the final spot.

I adjust the e-brakes before installing the IRS, using the ratchet mechanism
on them to get them close to touching but centered. The cable is no
problem to attach when fully done with the job.

Getting off the hard brake line connection is fun as well.

Each time, I have used the e-brake and it holds on a gentle slope. I never
use it after that time (or very seldom at least). I should but, do not deem
them necessary on flat ground.

My Jags have V8's and one has the whole exhaust routed under the IRS ala a Corvette, with two flanges...you will understand why when attempting to take yours apart.

I have not had to or did I, change any seals...no problems before or after
with leaking. The S3 cars use Locktite on the tapered bolts that hold the rotor on (?) not safety wire. Had to purchase one new bolt as one was broken
and it came already coated...MUCH EASIER than the wire.

 

I've always found getting the IRS lifted into position to be very awkward although a large plywood platform sounds good and might obviate the need for anything else.

Anyhow....

I use a jack (or grunt power) to lift one side of the IRS a few inches. Then, using several wraps of some heavy-ish utility wire I tie-off that end to the v-mount.

Then lift the other end a few inches and tie it off the same way.

Back to the other end, lift a few more inches, shorten the "tie off". Back to the other side.

After about 3 repeats (it really only takes a few minutes) the IRS is now safely suspended just below the v-mounts. The floor jack is used once more at each end for final positioning.

This is particularly helpful when working alone and single-handedly grapping with the unit.



I bed-in the parking brake pads by driving at 5 mph and slowly applying the parking brake until the car stops. Next time you drive the car repeat this a couple times and then couple more times the next time you drive the car.

That's it.

Go easy....you don't wanna get the tiny pads too hot!

In my experience this makes quite a difference in the effectiveness of the parking brakes.

Many complain about weak parking brakes but if they're lubricated, adjusted, and bedded-in they'll grip rather fiercely. Good function as a *parking brake*. You'll have to rev the engine to 2000+ rpm for the car to begin creeping forward.

Not all that great as an *emergency brake* to stop you from 60 mph, though

Once you get the p/brake working properly the best thing you can do is use it often. Doing so prevents the mechanisms from getting arthritis.

Cheers
DD

 

Thanks again guys! Sorry for my ignorance, but what is the "v-mount"?

Besides new parking brake pads, are there any other parts I should need to replace, or will I just need to clean and lubricate?

Thanks!

Eric

 

Vee-mounts are the four v-shaped (sorta) mounts that hold the IRS assembly to the underbody of the car. Worth replacing if the rubber is badly deteriorated.

Also order new retraction springs for the parking brakes. These look like metal fingers that bolt to the calipers

Cheers
DD

 

Well, I finally have the time to start working on my rear susp. assembly. I thought I'd continue this thread and add my comments and questions as I proceed. Some or all of my comments may be somewhere else, but I figured it couldn't hurt repeating it again.

Anyway, I backed the car up on some ramps so that I could get quick access to the rear end. I've been blasting it with PB Blaster for the last couple of weeks. First thing I tackled was the exhaust system since that seemed to be one of the bigger pains to deal with. A few thoughts. Loosen up the clamps holding the rear muffler on first and them detach the rear muffler from the exhaust pipe running through the IRS assembly. I twisted and tapped with a 5 pound maul. I'd also recommend taking the S curved tailpipe pieces off the very end. Then you can easily take the rear muffler out once they are loose.

Next loosen up the 3 bolts clamping the other end of the portion of pipe running through the IRS assembly. The reason you want to do the muffler first is so that the pipe running through the IRS assembly won't move around and will stay in place while you separate it form the rear muffler.

Oh, don't forget to put something under the 2 mufflers in front of the IRS assembly.

The next step I was going to take is unbolting the drive shaft. I tried the bolts briefly, but they were very tight and I needed to stop for supper. Any ideas or secrets for those bolts before I strip any flats on the bolts or nuts?

I'll keep posting more as I do something.

Eric

 

Use a quality made six side wrench, a flare wrench if it will fit is nice
and wide on the nut sides....

I have the (4) new V mounts listed for sale...sold the '72 before installing
them and changing out the 4:09 LSD for the 2:88 LSD...

See the ad at: (this site):https://www.jaguarforums.com/forum/p...nts-4-a-95834/

Contact me at mabryroger@hotmail.com

 

Well, she's out!!! Whoo-hoo! I was able to get 2 of the drive shaft bolts out, but then needed to rotate the drive shaft to be able to get to the other two. So I went ahead and disconnected the brake line and let it drip into a bucket. After that, I took out a pin in the parking brake assembly back up under the driver's (for LHD) seat. This released tension on the cable back by the IRS assembly. I then unhooked the spring at the end of the cable which allowed me to get the cable unhooked. Note, you will need to unhook one more spring which is keeping the cable assembly from hitting the rear brakes. One end of the spring is attached to the IRS assembly.

After disconnecting that stuff, I cut out a wooden rectangle per Roger's instructions and jacked up the IRS and put jack stands under the rear jacking points. I then could rotate the rear wheels so that the other two drive shaft bolts were now on the bottom and easily accessible. I removed both rear wheels and located them under the car as back up support. I then crawled under and removed the last 2 drive shaft bolts.

Oh yeah, prior to jacking the car up I went ahead and removed the bolts holding the radius arms to the body. Of course the radius arms didn't just come loose so I sprayed some more PB Blaster and moved on to the 8 bolts holding the URS assembly to the body. I loosened all the bolts and left 1 per mount in place until I was actually ready to drop it. I then went back to the radius arms and pried and tapped on them and they popped off. It's nice having a car originally form California and no rust!

Then it was time, I removed the remaining 4 bolts and started to lower the IRS assembly. I noticed that it was off center, weight-wise, towards the rear, so I repositioned it further forward so that the IRS assembly could rest on the arm part of the jack as it came down. This did the trick. I lowered it, slowly, down and luckily had just enough room to drag it out the back while still on the jack. I'll post a picture a little later. It's late lunch time now.

Eric

 

Here's a couple of pics showing the result. Overall it probably took ~5 hours to get to the point shown in the pics. That wasn't rushing. After the pics I started degreasing the assembly in preperation for disassembly tomorrow.