19 Leaking brake bleed nipple on new caliper

[LH16v]

Hi,

So I am in the process of replacing the whole brake system on my phase 1 19 16v. I have removed the bendix ABS and replaced with a standard mastercylinder and servo setup.

Ordered calipers from autodoc which I believe are "remanufactured".

So I bled the system using the 2 man method. Seemed to work well, got a strong pedal. On test driving, I noticed that the pedal felt a bit spungy - doesnt go to the floor but does not feel quite right.

I had another look at it and it seems that 2 of the calipers (1 front and 1 rear) have very slight leaks. These leaks seem to stem from the bleed nipples.

I have done the nipples up quite tight but it still seems to be weeping slightly. At first I thought I had the wrong bleed nipples so I even tried using the old ones but that did not make a difference.

Hard to say, but i think it is leaking from both the thread and the bleed hole as well. I dont understand and I am getting a bit fed up now. Any ideas?

 

[Duncan Grier]

Suspect it will be the inside of caliper seating area defect and not allowing the bleed nipple to seat correctly, or threads stopping the nipple to locate fully

How does it look, can you see any witness marks?

 

[LH16v]

Suspect it will be the inside of caliper seating area defect and not allowing the bleed nipple to seat correctly, or threads stopping the nipple to locate fully

How does it look, can you see any witness marks?

Admittedly I did not really look inside- I assumed that it would be like new.

My concern now is that I have now overtightened the nipple. Not sure what that means though- I guess I might have damaged the threads inside the caliper

 

[DaveL485]

The inside of the caliper should have a chamfer that matches the angle on the base of the nipple so it seats flush and blocks fluid flow.

 

[LH16v]

I lost my patience with it and did it up as hard as I could and now it seems to be fine.

Not looking forward to the next time I need to flush the system but that is a future problem.

 

[LH16v]

Bit of an update, this is driving me mad.

So in the end I still it was still leaking. The caliper that I got was remanufactured so I considered that they might have messed up the thread in the remanufacturing process.

Decided to get a new caliper as they are not particularly expensive.

Fitted the new calipers this morning, bled it and it is also weeping slightly. I am about to have a breakdown.

Been bleeding it with the 2 man method. Have my son in the car operating the pedal and I am opening and closing the bleed value. Got the caliper bled. Tightened the valve to a snug fit and I thought all was good. Pressing hard on the pedal for a prolonged period and no sign of a leak.

Left it and came back after 10 mins and found it weeping very slightly from the value around the thread. I wiped it up thinking it might just be some excess fluid from then bleeding process. Came back after another 10 mins and there was more fluid coming from the valve.

What am I doing wrong???

 

[Duncan Grier]

Caliper replacement same supplier as previous one?

Not sure you can really get it wrong, you tighten bleed nipple and it seals. Don't see how bleeding method makes any difference tbh

 

[Brigsy]

Probably just residual brake fluid from bleeding. Blast it off with brake cleaner.

Bleeding technique should not make a difference, its just getting the air out of the system.

 

[LH16v]

Thanks for the replies guys.

The calipers are the same.

I was thinking it might be residue from the bleeding process as well but I don’t remember it being like that for the other calipers.

Thing is that it is only a small amount, it’s not like it is even enough to form a drip. Just seems to be a small amount underneath the bleed valve.

 

[Brigsy]

Its common to see some fluid creep from the nipple area after bleeding, regardless of how well you clean it up.

 

[DaveL485]

Its common to see some fluid creep from the nipple area after bleeding, regardless of how well you clean it up.

This.

I usually hit it with brake cleaner at 100PSI to clear it out.

 

[LH16v]

Update time

So I was checking it regularly yesterday and it continued weeping. Kept wiping off a very small amount of fluid underneath the bleed valve. I was convinced it was leaking due to the amount of fluid that was there.

Got my son in the car on the pedal again tonight and as soon as he pressed on the pedal fluid came out. No signs of air in the system whatsoever- so now I have come to the conclusion that it was excess fluid from the bleeding process - all be it a lot more than I expected.

Followed Dave’s advice and went a bit crazy with the brake cleaner around the valve. Will check on it again tomorrow.

Anyway, thanks all for the replies!