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Beware - not all bleed nipples are the same


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Hi All,

I had gone just two miles on my first post restoration drive when it started to rain heavily so I turned round and headed home. When I looked at my brake fluid reservoir the fluid level had dropped by 5mm or so and was below the transfer hole between the two chambers. I soon traced the problem to the new (TRW?) bleed nipple fitted to a rear brake slave cylinder (original Girling). Fluid was weeping from the nipple which had been wound in extremely tightly with rounded corners on the hex section so I suspect there had been a problem getting it to seal. I removed the nipple and compared it to one from a Girling cylinder I had on the shelf and they are quite different in profile (see below). The TRW? nipple on the left has a shallower taper and does not come to a point. I put the Girling nipple on, nipped it up normally, and all has been well since. The car was returned with a fresh MOT so I am disappointed this was not picked up at the MOT station. I apologise if this topic has been covered before but a quick search under bleed nipples didn't reveal it.

Regards

Les

Rear bleed nipples.JPG

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Frustrating to see the difference between them, I'm guessing a new wheel cylinder has a different bore than the original and the bleed nipple fits that but they are not interchangeable.

Gareth

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On 11/4/2021 at 3:05 PM, Les Pettitt said:

Hi All,

I had gone just two miles on my first post restoration drive when it started to rain heavily so I turned round and headed home. When I looked at my brake fluid reservoir the fluid level had dropped by 5mm or so and was below the transfer hole between the two chambers. I soon traced the problem to the new (TRW?) bleed nipple fitted to a rear brake slave cylinder (original Girling). Fluid was weeping from the nipple which had been wound in extremely tightly with rounded corners on the hex section so I suspect there had been a problem getting it to seal. I removed the nipple and compared it to one from a Girling cylinder I had on the shelf and they are quite different in profile (see below). The TRW? nipple on the left has a shallower taper and does not come to a point. I put the Girling nipple on, nipped it up normally, and all has been well since. The car was returned with a fresh MOT so I am disappointed this was not picked up at the MOT station. I apologise if this topic has been covered before but a quick search under bleed nipples didn't reveal it.

Regards

Les

Rear bleed nipples.JPG

Transfer hole ? Do you mean baffle plate to separate front from rear brakes 

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Have to agree, rubbish parts, poor quality, similar problem. New nipple replacing an (original) rounded off one. Moss replacement from China, seized in the caliper and then sheared when I put a ring spanner on it, result, new caliper .........

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This issue sounds like a good one for the PQI initiative. Is anyone who suffered from this planning to raise this formally to the PQI-team?

Let’s help to improve our parts.

Cheers,

Waldi

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This is why I only ever fit brass bleed screws https://automec.co.uk/collections/fittings/products/brass-bleed-screws-unf

Yes I know theyre expensive but you dont get problems with them.

Stuart.

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18 minutes ago, stuart said:

This is why I only ever fit brass bleed screws https://automec.co.uk/collections/fittings/products/brass-bleed-screws-unf

Yes I know theyre expensive but you dont get problems with them.

Stuart.

+1 for brass bleed nipples. Beware metric vs imperial though.

Nigel

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4 minutes ago, Nigel Triumph said:

+1 for brass bleed nipples. Beware metric vs imperial though.

Nigel

Well obviously order whats correct for the calipers you have.

Stuart.

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On 11/6/2021 at 10:32 AM, stuart said:

This is why I only ever fit brass bleed screws https://automec.co.uk/collections/fittings/products/brass-bleed-screws-unf

Yes I know theyre expensive but you dont get problems with them.

Stuart.

The only thing I have against brass is that it age hardens and I feel that would make it prone to shearing off. I would prefer s/s.

Bruce

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1 hour ago, astontr6 said:

The only thing I have against brass is that it age hardens and I feel that would make it prone to shearing off. I would prefer s/s.

Bruce

Never had one sheer yet as they dont seize in place.

Stuart.

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1 hour ago, BlueTR3A-5EKT said:

Can I refer you to the OP picture of failed nipples that also had a flat tip like these stainless ones unlike the correct pointed brass ones.

Stuart.

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2 hours ago, stuart said:

Can I refer you to the OP picture of failed nipples that also had a flat tip like these stainless ones unlike the correct pointed brass ones.

Stuart.

Good point.  
I was waiting for someone to spot that Pike!

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Yes Neil,

I mean the baffle plate. There is a slot maybe 5mm x 2mm that is 10 or so mm below the top of the baffle plate. The fluid sits about 3mm above this slot in normal times.

The master cylinder is a new TRW one. I had a look at my original (1973) master cylinder and there is no slot so must be something TRW introduced.

Regards

Les

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