<VV> Blocked brake hose
hugo at aruncoaches.co.uk
hugo at aruncoaches.co.uk
Tue Oct 17 09:26:33 EDT 2017
### My experience is in the UK of course, which might be different.
When I worked in a main dealership in the mid-70's this problem was not
known. I THINK (although I don't have the facts) that the manufacturers
started 'lining' the hoses about in the 90's, and that's when this
problem first appeared, or it did when those hoses got a bit older.
Even a perfectly healthy brake master cylinder (unlike a clutch master
cyl) never goes anywhere near full travel in normal use, so you never
know what is lurking at the bottom of the bore! I've heard of a number
of cars where somebody has worked on the brakes & bled the system, then
a little while later their brakes have failed because they've pressed
the pedal all the way down when bleeding.
On 2017-10-16 19:46, FrankDuVal via VirtualVairs wrote:
> "This never used to be a problem - I think it co-incided with
> manufacturers changing to a new type of non-porous hoses - they
> suspected the earlier ones would let water in."
> They changed the rubber formula back in the 50s or 60s? That's how
> old some of the hoses with problems are.
> Again, like all brake parts, parts that save your life in
> emergencies, if the master cylinder is cruddy at the bottom of the
> stroke, then it should be rebuilt, not babied to not hurt it! Reminds
> me of the older people, back when I started driving, who told me not
> to step on the brakes hard, something might break!
> Yes to the hard harder test. It shows the weak parts that need fixing
> now. Despite those old people mentioned above! ggg
> Frank DuVal
> On 10/16/2017 1:18 PM, Hugo Miller via VirtualVairs wrote:
>> ### Yes indeed! If they had fitted the wheel cylinders the other way
>> up it would have been a lot easier. Like a lot of things however, once
>> you know what you're up against it's not too bad.
>> I will try that pressure test on the brake lines - as I said in
>> another post, this is not something I've encountered before - being
>> originally from the UK (now in Florida) the salt always eats steel
>> brake pipes from the outside before they can corrode from the inside.
>> I have heard of flexible hoses blocking or acting as one-way valves
>> before - usually this makes the brakes lock on - mine was the other
>> way around.
>> This never used to be a problem - I think it co-incided with
>> manufacturers changing to a new type of non-porous hoses - they
>> suspected the earlier ones would let water in.
>> Another thing to be careful of if you're keeping the old master
>> cylinder is never to push the pedal all the way down when bleeding -
>> if you do, the piston will be in parts of the bore that it's never
>> seen before, and there might be some corrosion in there that will
>> damage the seal.
>> Incidentally, for quickness I got brake shoes and hoses from
>> Autozone across the street from me. I'm amazed that I could order
>> parts for a car that's been out of production for fifty years at 8.00
>> on a Saturday evening and I'd have them by Sunday afternoon - you
>> don't get that kind of service in the UK! They didn't list the
>> cylinders so I got them shipped down from Clarks, equally fast but UPS
>> overnight was expensive!
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