Technical Brake bleed nipples

[Scoobysnacks]

Ok, this is going to sound like a very silly question, but what size are the brake bleed nipple nuts supposed to be?

I've tried all the usual sizes. 7mm slips, 6mm won't go on, and 1/4" doesn't seem to fit either! I'm thinking that the 6mm is the most likely, and that there is slight corrosion that's preventing it going on properly, but before I start knocking it on I thought I'd check!

 

[bredsticz]

My fronts are 8mm and the rears are 6mm

 

[invmatt]

8mm for the front and 7mm on the back for mine however I had to file one on the front & back as they were rounded.

 

[Scoobysnacks]

I think 7mm on the rear is right, but the nipple seems to have corroded so a 7mm doesn't fit. A 1/4" might do it, but my 1/4" combi has gone walkabouts, and do you think I can find someone that sells individual imperial sized spanners? Bleeping car!

Trying to get the hubs off to change the brake shoes on the rear, got a 32mm socket but now can't find my 1/2" drive (torque wrench) which is in a box somewhere after the move over the weekend. To top it all off, the boot on my jeep has decided to not open, so I need to fix that too. Never rains but it pours!

 

[MikeSalt]

Just check that it is not just corrosion preventing the smaller spanner from fitting.

And why are you taking the hub nut off to change the brake shoes? Not necessary at all. Simply remove the wheels, remove the location studs and pull the drum off. It's a good job you didn't find your 1/2" wrench since if you did get it off, you would need a new hub nut (a few £) and a torque wrench capable of 225 lb ft to put it back again (~£60). If you pulled the hub/bearing assembly off, and the inner race got stuck, that would be another £40 for a new assembly.

 

[m20b25]

Depends on the braking system. Most are standard 8mm however some bosch calipers use a 7mm nipple and lucas often use a 11mm nipple (dont know why) along with brembo. Its a pretty safe bet that it will be an 8mm spanner youll need tho If its rounded use a vise grips and plenty of plus gas

Ive never had to take the hub off to change shoes and Ive worked with some awful systems....! Theres something radically wrong if you have to do that. And as ststed above, the hub likes to come apart when removing them, they dont like abuse....

 

[tinytim]

Agree; do not take the hub nut off unless you intend to change the hub bearing; just remove the location bolts; the hub will be difficult to remove because there will be a ridge on the inner edge of the drum due to wear; lever off the plastic cap on the backing plate (difficult to see cos of road crap) you can then lever the shoes away from the drum to make removal easier; suggest replace slave cylinders as cheap and are probably about to leak; then you don't have to worry about the brake nipple just cut it off so you can get at the pipe union; strongly advise the purchase of dedicated brake spanners; also consider replacing drums and cables then you can forget about the back brakes for 100,000 miles; also get a fitting kit for the shoes as the old pins and springs will be corroded..........

 

[Scoobysnacks]

Hmmm, just remembered why I had to undo the hub nuts last time, it was to replace the bearings!

Still can't get the bleeding bleed nipples undone though!

 

[MikeSalt]

Try some proper brake pipe spanners first (you will need these for my next suggested step), but if you still have no joy, it is safe to assume they are seized, and likely that the cylinders are in a poor condition internally. Replace the cylinders too, and then you will have fresh, clean nipples to work with (ooh err !!!). You will need those spanners again for removing the rigid hose from the cylinder.

 

[tinytim]

sorry, the third hub in my post should be drum; you are going to have to change the cylinders; rear brakes are a faff to do and a safety/mot issue the parts are cheap so its worth renewing everything while you have it a apart......

 

[DaveMcT]

The drums might be OK and even within wear limits but if the contact surface is grooved, fit a new drum.

The slave cylinders are prone to failing so check inside the seals. Even if only 10% doubtful, change the cylinders. A seized bleed nipple suggests the cylinder is well past it's best anyway. Wheel (slave) cylinders are cheap and come with a new bleed nipple. Put some anti seize paste on the new bleed nipple threads for good measure.

The handbrake levers within the brake backplate tend to get sprained/distorted with use. Folks change the cable only to find not much improvement. So if that's old change it - much cheaper (and easier) than a new cable and easy while the brake is stripped down.