So close to getting the big overhaul on the jag complete, when one of the calipers has its threads strip in the bore for the bleeder valve.

Every bleeder valve on every caliper was a bit dicey to loosen and tighten, damn steel valves in aluminum threaded bodies!

I haven't measured the bleeder yet, but I believe it's and M10...? Maybe drill it out and tap it for 3/8 NPT and find a replacement 3/8 NPT speed bleeder?

Anyone experience this before?

What did you do?

Caliper replacement is not acceptable!

 

Ordered one new centric 'rebuilt' front brembo caliper from rockauto today, this will get the car going again!

In the meantime, I'm going to take my broken caliper and experiment a fix to blown bleeder bore threads. Considering boring it out and pressing-in a threaded-insert with fresh m10x1.0 threads. Who knows, maybe just chasing it with a modified tap might work...

To be honest though, the rockauto remanufactured brembo's work out to $150 per front caliper when you return the core. Rears work out to $120 per caliper when you return the core. To put that in perspective, the jag dealer charges $140 for 4 replacement seals in their caliper repair kit alone. New calipers are $800 per front.
Doing an outright replacement with rock auto centric rebuilt calipers means costs aren't too unreasonable really, so its hard to say if attempting a repair is even worth the hassle.

 

Sorry couldn't be of some help with this. Make sure you post up on how this goes for you. If it happened to you, it's happened (or will happen) to someone else on this forum. Information & experience are priceless.

 

My new centric rebuilt brembo arrived next day. It came loaded with pins, spring clip, pads, washers, banjo bolt, bleeders, bleeder boots, and painted the right original color, but no Jaguar R logo. (okay because i have a new set of brake decals anyways)

I haven't had time to attempt a repair on the old core, I might just send it back without even playing with it.

I think the best bet would be to punch out the bleeder bore to slightly oversized (M12 maybe, 7/16" perhaps?), thread the new bore you just redrilled, and find a matching valve. Here is a possible issue though, the bottom of the bleeder valve has a "pintle", a rounded tip that seats and seals the bottom of the bleeder bore in the caliper.
If going with a larger bleeder valve, or a bleeder valve for a different application for that matter, the 'pintle' might be different, and not 'seat' properly inside the bottom of the rounded bore in the caliper.

I may have to fire up MS Paint and take some pictures to clarify.

My other consideration, is to spin an insert/threaded sleeve, on a lathe, lets say spin it down to a 14mm outer diameter. You then drill and tap its inside diameter for M10x1.0 for the original bleeder. You then punch out the worn out bleeder bore to 14mm, and press-in or weld-in this new threaded insert you just made. You could even make it out of stainless so the threads would be more resilient this time, but you wouldn't be able to weld it in.

Really though, I am so impressed with the quality of the centric rebuilt brembo's, I am very tempted to just order new caliper all around as all that work is hard to justify when the rockauto centric's work out to $150 each...

 

an engineering shop could fit a helicoil (replacement threaded insert) the hole gets tapped out a size up then the insert is screwed it locks in position any decent engineering shop could do this infact you may be able to buy helicoils yourself and give it a go if you get good at it it could be an earner for you

 

Eh, I have a machine shop at work, I can tackle this one myself. Not sure if it's worth the work though if I can get a whole new caliper for $150 F, $120 R

If you were to pay a machine shop to perform this repair, despite being very straight forward, I can see it easily running well above the cost of a whole new caliper from rock auto. Certainly a better alternative than paying $800 per caliper new from Jaguar though.

 

Misalignment of the insert, or damage to the seal face can necessitate re-cutting the seat to restore the seal.

Here is an alternative that I haven't used, but it looks as though it could be less troublesome for the less experienced (or indeed the experienced).

Depending on the quality of the product, it could make the job quicker, cheaper, easier and more foolproof.

Bleeder Screw Assembly, Single - Speedway Motors, America's Oldest Speed Shop

Any one used this type of repair?

 

That looks like a good solution.
Anybody with first hand experience?

 

No. But, it is a Wilwood part and they know what they are doing.