Brake calliper bleed nipples - sheared :(
Turbo Mini Forums

Hi folks. Have started on the turbo conversion this weekend and one thing I've found is that on both front turbo callipers the bleed nipple closest to the brake line unions has sheared. The other two came out easily enough on both callipers but the 1 closest to the unions refused to budge :( Have tried tapping and using an extractor but they simply refuse to move.

The only other thing I can think of is to drill the whole nipple out and then re-tap the thread and fit new nipples. Has anyone else had this problem and can shed any light/advice on it?

Ta.

Jim

i have had this problem, and sheered my extractor in the nipple..

now i jsut take the caliper off when bleeding, as its possible to bleed that chamber, with the outside nipple if you hold the caliper upside-down.

some machine shops offer a nipple-removal(oooh er) service.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

LOL yeah - I've lost an extraxtor head too :( Now getting THAT out was a nightmare! I had to chisel the remains of the nipple away to get a grip on the tip of the extractor.

When you say you can bleed that chamber by holding the calliper upside down do you mean upside down as in the opposite of the calliper's normal mounted position? Or do you mean by tipping it on it's side?

I think I'm gonna try and drill it out manually and then re-tap the thread to clear any bits left blocking it. If that fails I guess I could try to drill a bigger hole and fit an over-sized nipple...?

Jim

wel if you think about it, brake fluid has to pass from that inner lower chamber to the outer lower chamber, it does this via a hole drilled in teh bottom bit of the caliper that goes over the disk, so if you can open the outer-lower nipple you can get air out both chambers if you put the caliper upside down on teh disk, then bleed, then the right way up, then bleed etcetc, tricky and v anoying.. but saved me possibly ruining my caliper by drilling out the nipple. And saved me buying another as i was skint...

if you sit the caliper so the outside nipple is the top most point you wil need to put something between the pads to stop the pistons popping out :)

redrilling is a problem, the nipple seats and seals against the cone shaped seat at the bottom of the nipple drilling, if your dril bit scores this, or makes it un-even the nipple wil never seal.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Well, I managed to drill the b@st@rd out, re-tap the thread and fit another nipple. It all seems a-ok and doesn't leak now :)

On the down-side, the other calliper isn't proving easy at all :( One of the pistons is well and truly siezed inside the calliper and the sheared nipple on THIS calliper seems to have heat-hardened at the tip, so I've managed to drill 90% of the way down through the nipple but simply can't drill through the last 2 mm.

The tip of the nipple is pointed so as long as it can fit snugly in the 2mm opening at the bottom of the 7mm threaded shaft then it seals just fine.

Am near to either having a hissy fit or possibly sobbing quietly on the floor as I've been trying to drill this s*dding nipple out for the best part of 5 hours now!! Grrr......

I have had the same problem as you guys , including shearing the stud extractor. I managed to get them drilled out eventually, and fitted a slotted screw in place which seems to work ok for now. Does anyone know where to get the original nipples? I have tried the local Rover dealer as well as Minispares etc but no-one seems to stock them now.

The nipples are sold by Minisport at ?1 each.

Not too impressed with their service thoguh as I ordered 2 on Friday and they promised 1st class postage on the same day. No sign of 'em on Saturday OR today.Had to p1ss about swapping nipples from one calliper to the other and back!

I managed to drill down through the 2nd siezed nipple and the re-tapped shaft now seals a-ok with a nipple in place. I'm also painting the callipers red and have taken a photo. Just look at the wierd but cool things my flash seems to do - I wish the paint looked as sweet as this IRL:



The above also shows the brake line adaptor kit sold by Huddersfield Mini Spares. It's actually a kit made for converting bikes from 2-pot to 4-pot callipers!

Jim

watch how you position the hose that joins the 2 bits, you have to angle it so it doesnt hit the driveshaft/innerCV/wheel.

My cameral also shows my red calipers as an orangy color

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

i curently run s disks and calipers on my mini
but one of the callipers has had the threads for the nipple damaged.............
if i try to tighten the nipple it overuns :(

any sugestion on what i could try

Edited by speedfreaq on 16th Mar, 2004.

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

take it out to a bigger thread, and fit an oversize nipple.. only thing i can think of im afraid.

any decent machine shop should be capable of this...

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Been there done that, I bought my calipers new but helped my mate to drill the broken remains out and chase the threads. You don?t need to drill all the way since the bottom of the screw is smaller OD anyway. Just drill the threaded portion out and remove what?s left. 5,5 mm or max 6 mm drill should still leave the threads intact if you drill exactly in the centre. The thread is M7 if I remember correctly. Clean the threads and fit a new bleed screw. They are available from any automotive shop. The size is not unique for Metro, I believe rear cylinder bleeds are the same size. Fit the new once sith copper paste and you should no have further problems.