Replacing rear discs on an S3

I finally found the motivation to get the handbrake fixed on my 1974 S3 OTS.
For a reason unknown to me, one of the RH parking brake pads had disintegrated and rendered the parking brake useless. It may have been caused by me reusing the “forks” that retract the break pads when releasing the handbrake. Anyway, I’ve heard some squeaking from time to time and decided to replace discs and break pads at the same time.
Now to my problem. I can’t get the :face_with_symbols_over_mouth: discs off. Following the manual I am finding that even after tapping the flange bolts as far back as I can and dropping the suspension as much as the IRS cage will allow, the flange bolts seem to be just long enough that the disc won’t come off.
Is there a trick ? Cutting 1/4” off the flange bolts ?
Taking the bottom plate off the IRS cage ?
Thanking for your help in advance … Ole

Ole, sounds like you haven’t removed the calipers? You shouldn’t have to knock the flange bolts back.

Ole, those flange bolts are pressed into the flange, should not be “knocked back”.

The calipers are off.
As per the workshop manual, the bolts are supposed to be tapped back as far as they can. They hit the output shaft mounting “thingie” and therefor doesn’t go back far enough to make the disc clear them.
As seen in the second photo, the disc is hitting the lower wishbone
Back to my original question.

Ole. I don’t know which manual you are refering to, but Factory Manual doesn’t describe that method, need to swing the lower wishbone out of the way, disconnect the shockers.

1 Like

+1 disconnect the shockers. On an S2 that was necessary.

Hello Ole - I have never worked on my brakes yet, so I am just asking, not stating a fact - if you lift the wishbone to a horizontal position, would you be able to remove the disc from the studs, then lower the wishbone and remove the disc by lifting the disc up past the wishbone then down and out - again just asking from looking at your photo - Tex Terry II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 3/22/2020 2115hrs. EST USA.

Sorry Ole, just checked OE Manual, does say knock back bolts, but also says remove shocker lower fulcrum pin (allows wishbone to swing out of way).
Must admit that in 50 years of working on E’s, never had to knock the bolts back.

Well, the IRS “bottom” plate seem to be the one in the way of moving the lower A-arm all the way to clear the disc, so it has to go.
FYI, the shocks are disconnected to allow for the A-arm to move as far as possible.

If the bolts were to disappear could you lift the disc far enough to clear the lower wishbone?

If so, why can’t you remove the bolt closest to the camera lens in your first picture, rotate the disc 90 degrees and remove the bolt that is not free of the “mounting thingie” and then repeat for the remaining two bolts. t

If it was only that simple.
Greg Weldy (a local MD and serious E-type restorer in Maryland) told me many years ago that my diff wasn’t original to my car.
Today when I see the drawings and pictures of IRS’s, it does look as if there is more distance behind the flange than on mine, allowing the bolts to be pushed further back.
I’ll get the bottom plate off the cage tomorrow and see if that does the trick.

A new aluminum diff cover will be ordered to address the leaky stamped sheet metal piece.

… Ole

The aluminium diff cover will have a hole for a speed sensor you don’t have so you’ll have to fab up a plate to cover it.

kind regards

1 Like

Marek, this is the cover I plan to use. Probably the toned down unpolished version.

I used a jeep version which has larger capacity…

. It was around £65 delivered from the States.

Ole, on checking Factory Workshop Manuals for the E Type, S1 to S3, none say to knock the flange bolts back, but the XJ/XJS Manuals do. Does’t make sense.
In all my 50 years of working on IRS’s I have never had to knock back the bolts to remove the disc, have always removed the bottom plate and swung the wishbones out of the way, whether it was in the car or out.

Bottom plate off and full clearance to replace discs.
Thanks for the insights and advice.

Can you get the calipers off with the IRS in the car ? They are tricky enough with the IRS on the floor.

On the S1 with the Dunlop caliper it is easy because the caliper is mounted on a seperate bracket that the bolts are accessible thru the disc.
With the Girling caliper it can be done but it’s a pain, though you can split the caliper if you want to do it that way.

There’s some story about unbolting the caliper and then rolling it around the axle to the back side to get it out. Dunno first hand, though, I worked on mine with the IRS out.

Kirby, I took a look at the diff today and can not imagine undoing the bolts and sliding the calipers down to get them off to replace the discs.

I started cleaning up the calipers, which I rebuilt and had powder coated about 8 years ago, and after maybe 4-5000 miles the rubber seals around the SS pistons look like what you see in the picture. Is that normal ? Both calipers, all four seals more or less the same.

Any insights ?
If this is normal and I “never” drive it in the rain, should I replace ?