Rear brake calipers

Hi all.

I’m in need of some help with an issue on the rear brake caliper on the +2.

In the section on the rear calipers, J.6, there’s a note that says ‘Under NO CIRCUMSTANCES MUST the two halves be separated’, referring to the paired halves that make up the rear caliper.

I read this as meaning that you’ve got to bolt those two halves back together, and can’t swap them between assemblies. I can’t see any reason why you shouldn’t separate them and rejoin.

Has anyone split a caliper and rejoined it? Is there anything special about the O ring seal that goes between the two halves?

Sean.

Hi Sean,
Most of the Girling/lockheed calipers came with this warning.
As far as I have heard on the classic car sites I frequent if you can get the O rings there is little problem with separating them, although I don’t think there are published figures for bolt torque when you put them back together
Cheers
tim
(PS you going to Donnington this year?)

Hi Tim.

Thanks for the reply.

Yup, I am planning to go to Donnington this year. I missed it last year, so I’ll make the effort this time round. I spoke to SMS yesterday, and it appears that illness etc has taken its toll on their work schedule, but that my car should be in the spray booth some time in the next couple of weeks. Fingers crossed; it should be home before Donnington.

All the best.

Sean.

I seem to remember bolt torque figures for calipers being given in the past on the site. Check the archives.

I took a look in the archives and have found reference to using standard torque values for the size of bolts.

The car’s not been on the road since I refurbished the calipers and now’s the time to convince myself what I’ve done is ok, hence the thread.

When I refurbished the calipers I found that I just couldn’t get one of them clean without splitting it, and once apart couldn’t see what the issue was with splitting it. Much easier to work on. I torqued the bolts up to the standard for the size of bolt and I think I used some thread lock also; it was some time ago, and it’s been bothering me ever since; I made a note to revisit it. I have pressure tested it with standard foot power and it’s not leaked. I ended up re-using the square section o ring seal, which bothers me.

Sean.

That’s what I did, too. Static tests show no leakage, but I can’t brake in anger yet, that is, until I install the engine. I don’t expect any trouble with them, though.

The Calipers have a special “Square in cross section” O ring between the two halves and should be replaced with the same kind. Its made of the same material as the caliper piston seals. Dave Bean Engineering sells them under part # 007 J 4908 . I have reused the O ring between the split halves that came out of the same caliper with out issue. I have split calipers before and I bolt them back together with Locktite using the listed torque values for the 5/16 bolts - 13 lb/ft and 27 lb/ft for the 3/8 boltss.
Maybe some one should scan the catalog and put it online, lots of important info in it, or spend the $5

Gary - edited to correct spelling and other issues

Oops! I see that my previous post was incomplete. I did use the correct O-rings; got them from RD. But otherwise, it was a straightforward process.

The info on the o rings was just what I was looking for; I did end up re-using the original seal as I was not convinced that the o rings that I found were correct for the job. The material was the concern rather than the cross section.

I guess I’ll be getting in touch with Dave Bean Engineering.

Thanks for the information. It’s so long now since I rebuilt the calipers that I’ll feel more comfortable if I check the seals on both before installing the engine and amplifying standard foot pressure with the servo.

All the best.

Sean.

UK supplier of the special square section seals and brake fluid compatible is Powertrack
01753 842680
44 1753 842680 (International)

Fax: 01753 842680

E-mail: [email protected]

For what it is worth, I used new grade 12.9 bolts to join the two halves together!!