Sweating brake fluid!

[MikkiJayne]

I checked the hose again this morning and sure enough, sweating fluid still. Damn thing is like old dynamite sweating nitro! Here are some pics of the paintwork damage:





The hose is £30 from TPS. Vexing, but not the end of the world.

The reservoir however... £240!!!!



For that much I can buy a whole master cylinder and reservoir for a 4 or 6, so sod the '8 tax' unobtanium stuff - retrofit the cheap versions Initial tinkering suggests a C5 RS5 setup will go in, and the bore is identical and the reservoir for that is about £35...

[MikkiJayne]

Had a phone call from TPS today - after 2 weeks of being on back order, the hose turns out to be NLA

Not sure what I'm going to do with it now tbh. Hose suppliers look at me like I've got two heads when I ask for brake-fluid resistant hose. Apart from HEL of course, but theirs isn't big enough. The factory rubber hose has such tight bends that OE clutch hose won't bend that tight, nor could I bend metal pipe that tight either.

Possibly I could cut the bends off the hose and use alloy tube for the main run across the bulkhead. Or maybe just encase the original hose in adhesive-lined heatshrink...



Oh, and after tinkering and measuring and pondering, there is no space for any other model's fluid reservoir The recess in the bonnet is so tight around the reservoir and the m/c is so high in the car there's no option other than the proper one. I'm going to try various ways of cleaning my original reservoir in the hope it won't sweat with new fluid, and if that fails I'll import a new one from ECS. Its £150 to buy in the US with the crap exchange rate, but even with postage that's cheaper than here. I have plenty of friends in the US who can post it for me.

[Nick Jones]

Guess I'm glad mine doesn't have EPS then.......

For brake fluid you need EPDM or EPDM lined hose
https://www.merlinmotorsport.co.uk/p...100mm-m-sph8-4

Not sure what to suggest re. the bends. I have used the metal insert method before for NLA/stupidly expensive boost sensor pipework on my A6.

Nick

[MikkiJayne]

Thanks for the link I'll ask what the minimum bend radius is. Maybe it'll work.

[MikkiJayne]

I've given up messing about with this as its a battle I can't win.

No off the shelf EPDM hose will match the bend radius of the factory hose so I've covered it in adhesive-lined heatshrink. Polyolefin heatshrink is basically the same as polypropylene which is what the reservoir is made of so it should be resistant to brake fluid on the inside and waterproof on the outside. I think water vapour / condensation was allowing the fluid to get out by osmosis so hopefully isolating it from that will solve the problem.

I've tried cleaning the black streaks out of the reservoir with everything I have in the workshop: ultra-aggressive degreaser, acetone, celly thinners, contact cleaner, wheel cleaner (phosphoric acid) and even hydrochloric acid. Nothing has any effect whatsoever They come off easily with a cotton bud, but of course you can't get to 99% of the inside of it so it looks like they'll be staying. I'm just going to put it back together and see how it behaves.

Not the most successful part of this restoration

[Architex_mA8tey]

There's a company in Swindon called PIRTEK who it would seem can make up almost any type of hose or pipe that you need along with any type of connector - might be worth looking them up and phoning them for a chat?

[Delboy]

Is the line your having problems with a high pressure line or just a feed line from a reservoir?

Depending on the end fitting and rating you could have pipe bent to replace the long hose section and have short sections of hose either end, which is the normal way to design systems.

I used to work for Pirtek and they can indeed do quite a lot but most of there stuff is related to industrial hydraulics but some depots have things like tubing, good ridge style hose and fittings etc so could well be a good place to start.

They are all over the UK too.