Brake pipe repair (not replacement).

[Little Dog]

Found this thread with good info on brake pipe replacement

https://www.a2oc.net/community/inde...nes-crusty-and-now-leaking.25992/#post-290856

I accidentally caught the end of one of the longest pipes while using an angle grinder to remove the hand brake cable in sections. Its safe to move around in the garage but its not going back on the road without a repair. I want to replace the last 15cm of pipe therefore avoiding a major pipe replacement along the length of the car.

Has anybody ever used one of these? https://www.ebay.co.uk/itm/HAND-HEL...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

I've not measured the pipe yet but the tool is also available for metric pipes.

 

[Little Dog]

Got a tool on order but not the one above. There are three standards for the flare:
SAE for older UK cars with imperial threads ie classic mini
DIN 4.75 older cars with metric threads (apparently before 2005)
DIN 5.00 newer cars with metric threads
Tracking down clear data specifying what is on my A2 wasn't possible. So went for DIN 4.75.

Did I get it right / wrong?

 

[Kleynie]

I’ve used flare fittings before on fridge pipework, shouldn’t be a problem if you have the correct size.

 

[Little Dog]

Anybody know where the vent hole is?

Usually in the reservoir cap, but isn't, I need to close it off to minimise fluid loss

 

[Skipton01]

The vent in the system will be at the topmost part of the circuit, which is the reservoir. There's no hole as such, but don't worry about fluid loss - you will have to bleed the system fully anyway to get fluid to the caliper, once the flaring is done.

 

[steaman]

Just put a thin rubber glove on top of the reservoir before putting on the cap. The vent is in the cap and will be blocked by the glove.

 

[Little Dog]

OK I can flare cunifer, need a deburring tool and then I can make a replacement pipe. Not sure about using that on steel under the car to repair a pipe though:

 

[steaman]

Is this what you need?
https://www.ebay.de/itm/5-Meter-PKW...481236?hash=item5b23132554:g:gJ8AAOSwyWZZUNXC
or:
https://www.ebay.de/itm/Bremsleitun...569248?hash=item2aa0830be0:g:jYEAAOSwATxaiUDN

 

[Little Dog]

That would make life easier. Must make use of a compression ring?

Would I trust that? Probably not with cunifer but would probably be OK with steel.

 

[steaman]

It works for water pipes, so why not. I worst case you would get a tiny leakage.

 

[Kleynie]

That will definitely work, I have used these up to 1500psi on small bore inert gas pipework.

 

[Little Dog]

Must make use of a compression ring?

Would I trust that? Probably not with cunifer but would probably be OK with steel.

I'm going to flip the whole argument over. I'm going to trust it with cunifer because the compression ring will bite into the softer pipe. However possibly not with steel as the same compression ring would not bite into steel. Can't have it both ways with a compression ring?

The thing I like about a flare is the seal is determined by the torque I apply to the nut; can get it right for both materials.

 

[Little Dog]

This is the damage I had to repair:

Had to cut the handbrake out using an angle grinder. Caught the brake pipe and it looks like it must have nearly gone through.

The flare tool is quite difficult to use under the car. The pipe is plastic coated and this has to be trimmed back, the fluid has a siphon effect and drips constantly. My first attempt produced a good flare but the tools slipped due to my gloves being covered in brake fluid and the pipe bent at the rear of the tool:

Loosened the sill trim and tried again. This time I stopped the flow of fluid by detaching the pipe at the ABS unit. The ABs unit was plugged and the pipe blown through. I now have a better repair with the connector between two clips under the sill.