Britpart master Cylinder-trustworthy?

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Alpinewoodsman

Well-Known Member
Posts
146
Location
French Alps
After an interesting total brake failure on a steep mountain road, I'm making a few repairs to my braking system.
Vacuum pump is OK, fluid level is OK with no obvious leaks, and given the sudden and total lack of any brakes, I'm 99% certain it is the master cylinder.
Are the Britpart ones decent, or are the more expensive ones better?
1986 2.5 turbodiesel, LHD if it matters!

As I'm doing the master cylinder, I'll renew the fluid- about 2 litres, isn't it? I'll also be fixing the front bumper, track rod, and a few other bits that bent in the process of stopping.

And thanks to the informal Land-rover assistance network, for helping to pull me out of the snowbank!
 
Whatever make you buy, pop the rod and seal out and take a look at the seal itself, is it well shaped/nice edges etc? if so its good to go.
If car stands for long periods after refitting the seal and rod stuff some rubber grease into it to stop the piston seizing through rust, note not on the fluid side!

1 litre should be enough, though you can never have enough, buy it in 1 litre pots that way if you dont open the second it will keep for years.
 
If your master-cylinders fail brake fluid should leak down the back of the pedal and be evident on the floor.

Currently standing on mud, so hard to check. Level in the reservoir is OK, so I wasn't looking for a big leak.

Once I have steering back, I'll get it in a flat dry garage, and can check better...
 
Can someone tell me how long brake fluid lasts in a sealed container once you used some.
I’ve got a couple of half full bottles of DOT 4 that are a few months old. Can l use it?

How long before it becomes unusable? After l bleed the brakes (using a pressure bleeder) l generally pour the unused fluid back into the bottle.
 
Can someone tell me how long brake fluid lasts in a sealed container once you used some.
I’ve got a couple of half full bottles of DOT 4 that are a few months old. Can l use it?

How long before it becomes unusable? After l bleed the brakes (using a pressure bleeder) l generally pour the unused fluid back into the bottle.

Easiest way to check it is with a cheap water content tester of evil bay or similar - but yes, provided it has been in a sealed container it should be fine to use.
 
Brakes are a safety critical item, right? Why would you be considering fitting a possibly dodgy part for the sake of saving a few quid? This might sound a bit evangelical, but I've made that mistake, thinking that OEM parts carry an outrageous mark-up that isn't justified. This might be a justifiable accusation for some things but brakes? I fitted, for example, pattern brake pads before a long offroad trip a few years back. I regretted that decision when the front brakes failed (you know, the ones that do all the work on a Defender?) at the top of a 6000ft mountain pass. The "biting" part of the pads had disappeared into thin air. It was a very interesting descent and a diversion into the next country to get replacements...OEM...very expensive, but still working as designed after another 2 demanding trips.
 
Did you have any braking at all, even if you stood up on the pedal? If you did, I'd suspect the vacuum pump as it happened to me recently. If the pedal went to the floor, look at the master and slave cylinders (assuming good fluid levels). A drip of fluid down the pedal arm is a giveaway,as s/o ahead of me said. If the latter needs to be replaced it's a timesaver to do both since you'll be in the same mess anyway.
 
Did you have any braking at all, even if you stood up on the pedal? If you did, I'd suspect the vacuum pump as it happened to me recently. If the pedal went to the floor, look at the master and slave cylinders (assuming good fluid levels). A drip of fluid down the pedal arm is a giveaway,as s/o ahead of me said. If the latter needs to be replaced it's a timesaver to do both since you'll be in the same mess anyway.

No braking at all. Trying it static this afternoon, no resistance on the pedal with engine on or off, other than return springs.

Fluid was well above minimum on the flat.

Disconnected the vacuum hose, and it would stick to my finger with the engine running. Not impressive, but clearly working at least somewhat.

I though even without vacuum/servo working I'd have some brakes if I push hard enough, so nothing at all had to be master cylinder...
 
Can someone tell me how long brake fluid lasts in a sealed container once you used some.
I’ve got a couple of half full bottles of DOT 4 that are a few months old. Can l use it?

How long before it becomes unusable? After l bleed the brakes (using a pressure bleeder) l generally pour the unused fluid back into the bottle.

Literally years in a sealed tub.
In my eyes once the fluid is out of the container its scrap, used or not.
 
No braking at all. Trying it static this afternoon, no resistance on the pedal with engine on or off, other than return springs.

Fluid was well above minimum on the flat.

Disconnected the vacuum hose, and it would stick to my finger with the engine running. Not impressive, but clearly working at least somewhat.

I though even without vacuum/servo working I'd have some brakes if I push hard enough, so nothing at all had to be master cylinder...


Chcuk some fresh fluid in the reservior and get pumping and get someone to look around the motor for leaks/bulging hoses etc.

Being a split system there should be more than one seal so could have failed internally and not leak externally.
 
I would get started on making sure all the bleed nipples are free. On my old 110 in changing one rear brake pipe, by the time I had gotten a brake joint to open cleanly I was all the way to the front and then ended up replacing all flexis, pipes and brake cylinders as the bleed nipples were never coming out without stripping threads.
 
I would get started on making sure all the bleed nipples are free. On my old 110 in changing one rear brake pipe, by the time I had gotten a brake joint to open cleanly I was all the way to the front and then ended up replacing all flexis, pipes and brake cylinders as the bleed nipples were never coming out without stripping threads.

They were all bled and the system topped off by a professional garage three months ago, so the bleed valves should be fine.

Also, it is currently sitting outside, and I can't yet get it into the garage to work on the brakes in the level, clean and dry.

Plan is replace the tie rod and do an approximate wheel alignment. One is on full lock and the other is pointing straight ahead! Then I can drive it onto hard standing, pressure wash it, ( fun in January in the Alps...) then get it into the garage to do the brakes. Clean will make everything easier, including checking for leaks.
 
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