refurbing rear calipers

[Mr Pharmacist]

You might struggle to get any other calipers that are a bolt on fit I think.

You can get new adjusters - Ferrari's used ATE brakes and some parts are the same (Ferrari tax is more than Porsche tax!)

Have a look here:

http://www.superformance.co.uk/246/brakes.html

Or get in touch with Eric Shea at PMB Performance to see if he can supply you with the parts

[Dean.s]

Thanks for the link Stuart, a bit pricey but when needs must. Oh and that exhaust is loud !

Anybody know the thread size of the adjuster? It's m10 but i don't know the pitch size.

Picked my tools up and reassessed the caliper tonight. I have an engineer who is willing to take a look at the threads but i have no idea when i can get the bits to him. In the meantime if i can sort it myself i would like to as i'm also under time constraints.

Also discovered that euro car parts does a refurb on these calipers. To what extent i don't know. All i was told was that they get sent off to be done.

[Mr Pharmacist]

These people have refurbished a good few 914 calipers. Last time I enquired it was £140 per caliper for the rears I think.

http://classicbrake.co.uk

That exhaust isn't loud (well not compared to my new exhaust )

[davep]

Anybody know the thread size of the adjuster? It's m10 but i don't know the pitch size.

I am not sure what you are referring to here. The outer adjuster uses an Allen (HEX) key to turn, and it is not 10mm.
The inner adjuster also uses a key to turn, and it is a "gear". You mention the threads are stripped, so you have me confused.
Can you post a photo of the problem please.

[Dean.s]

Dave, it's the coarse thread on the adjuster. The thread screws into the rear of the piston. It's something like m10 x 1.75 or m10 x 2

[Mr Pharmacist]

I might have one in my collection of parts somewhere - if might not be the correct size (there are 2 sizes of these) and it might be in crap condition, but I might be able to measure it if I can find it

[davep]

Okay, understand now. That is quite a coarse thread, not a typical machine thread. I'm not sure how that can be fixed. With all the dozens of rebuild I have never had one stripped. I would just replace it if I was doing it. My problem is the outer hex key being stripped out on half of the adjusters.
Here is some photos of parts:
http://www.914world.com/bbs2/index.php?showtopic=77361
And yes, that piston face was wearing on the brake rotor; The pad backing plate was worn right through.

[Dean.s]

Bit of an update. It seems that I cannot buy an m10x2 tap or die. I have details of a machinist and will go see him tomorrow for his opinion on whether he can do something.

Both sides on the handbrake side of the caliper have the same problem. I think the female thread has stretched and that's the problem in reassembly.

Strange but maybe it's been used under heavy handbrake use with a previous owner.

Failing the ability to repair or replace these bits I will look into the 911 turbo caliper conversion.

[914 KEV]

Both sides on the handbrake side of the caliper have the same problem. I think the female thread has stretched and that's the problem in reassembly.

Strange but maybe it's been used under heavy handbrake use with a previous owner.

Failing the ability to repair or replace these bits I will look into the 911 turbo caliper conversion.

I doubt that very much, more likely caused by someone not knowing what they were doing and forcing the pistons back in using a crowbar!
I have always bought my rear caliper inner spares from Superformance and by the way the cost of the parts you need is still very small cost compared to doing a 911 Turbo brake conversion!

[Dean.s]

Both sides on the handbrake side of the caliper have the same problem. I think the female thread has stretched and that's the problem in reassembly.

Strange but maybe it's been used under heavy handbrake use with a previous owner.

Failing the ability to repair or replace these bits I will look into the 911 turbo caliper conversion.

I doubt that very much, more likely caused by someone not knowing what they were doing and forcing the pistons back in using a crowbar!
I have always bought my rear caliper inner spares from Superformance and by the way the cost of the parts you need is still very small cost compared to doing a 911 Turbo brake conversion!

Do you know if the piston comes with the spring loaded threaded part inside or is it an empty cylinder? Every picture i see is an empty cylinder but no one lists the centre part. That's the only piece i need x2, both geared adjuster bolts are fine.

[davep]

Pistons are just that, no guts. I may have some spare guts if you want me to look.

[Dean.s]

Dave, i would appreciate that. My 2 are off to the machinist tomorrow but i won't know if they're salvageable until he's looked at them properly.

[Mr Pharmacist]

Dean, I have one piston with the M10 gubbins inside if it's any use to you

[Dean.s]

Thanks Stuart I'll bear that in mind

[Dean.s]

I picked up the internals today from the machinist. Apparently the closest thread size he could calculate was 3/8 bsw! 13 threads per inch if I remember correctly.

Anyhow both insides now screw in nicely, I don't anticipate any wind on issues as before. There is no play in the threads when they're connected either.

If I get back early enough tomorrow I'll rebuild and paint them ready for fitting on Saturday.