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Brake master cylinder


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Greetings, oh sage ones.

I had to replace my brake master cylinder and servo 4 or 5 years ago. Although the servo failed almost immediately, the brake cylinder seemed OK. Until Thursday. We’d been out to see friends, about 20 miles away. Returning home, about a mile from home, the brake pedal went straight to the floor. With pumping, I was able to recover a small amount of pressure. 

The following morning, the pedal seems fine again, but I have lost confidence in it. Can anyone suggest where I might get a good one, please?

regards,

Austin

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Hello John,

no to both those questions. I believe the problem is the ‘tipper’ valve. The cylinder was manufactured by TRW, and I recall reading somewhere that they had quality issues.

Austin

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33 minutes ago, Austin Branson said:

Hello John,

no to both those questions. I believe the problem is the ‘tipper’ valve. The cylinder was manufactured by TRW, and I recall reading somewhere that they had quality issues.

Austin

They're garbage Austin, I had one behave the same way and returned it, better off getting an original m/cyl reconditioned.

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Just now, Waldi said:

Hi Austin,
Ask Past Parts, they reconditioned mine.
Waldi

Hi Waldi, unfortunately I don’t have an original unit to be reconditioned. Any ideas where I might get one?

Regards,

Austin

Just now, Waldi said:

Hi Austin,
Ask Past Parts, they reconditioned mine.
Waldi

 

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Hi Austin,
I would just give them a call, or maybe someone has an old original for you?

Waldi

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I also have an interest in this, the one one the car which might be original or not was leaking so I tried new seals, still leaking so bought a new one, this also leaked so got a replacement, this has worked but leaked a little bit and then seemed to be ok, have used it for 4-5 years now but will get the original refurbished if I can get it confirmed that it’s actually an original part...

 

 

Magnus

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14 hours ago, Austin Branson said:

Hi Ian, any suggestions on where I might get an original unit?

Regards,

Austin

I got mine from Conrad, he's on here as "Openroad" worth asking him.

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My original master cylinder (1972 vintage) started to leak some years ago so it was replaced with a new unit, this lasted a couple of years then I changed the brake pads and wheel cylinders, within 100 miles the master cylinder failed in a very big way!

The reason I am told was the new parts altered the travel of the cylinder piston past its original stop point and because the material of the new cylinder is to soft there was a slight ridge at the old stop point which ruined the seal, I then bought another new cylinder which the vendor assured me was ok and the issue had been resolved, this started to leak after 4 or 5 thousand miles and of course this happened in the middle of France on the way home from a holiday.

I now have the original 1972 cylinder back on the car after being refurbished by Past Parts with (touch wood) some 12 thousand miles and no problem.

George 

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  • 4 weeks later...

Hi guys, as Waldi suggested,  I contacted Past Parts, and they will sleeve, refurbish and plate the exterior of my TRW m/c. 

I believe the cost is £130, not sure if that includes VAT.

The problem for me is that I live in France. I posted the m/c on Monday May 25, but PP only received it last Thursday! That’s nearly 3 weeks. PP are quoting 3 weeks for their work, and then I’m probably going to hit another 3 weeks delay in the postal system. That’s a total of around 9 weeks. That’s most of my summer down the toilet.

The other issue is cost - nearly £20 to send it, probably a similar cost for return. I guess the postal people have to cover their increased storage costs!

Right, spleen vented. I’ll let you know how the m/c looks when it gets here.

Thanks again for all your help and support.

Austin

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Had mine done recently by past parts, quoted 3 weeks ( I think this is a standard) but had a mc and servo both reconditioned and back in Just over a week. Guess it depends how busy they are. Hope your lucky.

 

Edited by Phil H 4
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  • 4 weeks later...

Hello folks.

I got the reconditioned cylinder back from Past Parts yesterday. Fitted it yesterday afternoon, and took it out for a spin, and there is still a problem. About one in ten depressions, and the pedal goes about an inch further than usual. Also, the reservoir is flooding, and forcing fluid out of the breather hole in the lid. I’ve just had a long conversation with Nigel, he thinks it might be something to do with the servo, and suggested lubricating the output shaft from servo with rubber grease at the seal. Can this be done without disconnecting the brake lines? I have rubbish knees, and bleeding brakes is difficult.

Austin

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32 minutes ago, Austin Branson said:

Hello folks.

I got the reconditioned cylinder back from Past Parts yesterday. Fitted it yesterday afternoon, and took it out for a spin, and there is still a problem. About one in ten depressions, and the pedal goes about an inch further than usual. Also, the reservoir is flooding, and forcing fluid out of the breather hole in the lid. I’ve just had a long conversation with Nigel, he thinks it might be something to do with the servo, and suggested lubricating the output shaft from servo with rubber grease at the seal. Can this be done without disconnecting the brake lines? I have rubbish knees, and bleeding brakes is difficult.

Austin

You can just unbolt the cylinder off the servo and theres enough give on the pipes to move it enough to get to the pushrod.

Stuart.

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Hi Austin,

have you checked the gap between the servo push rod and the cylinder piston? A simple test to increase the required clearance is to loosen the 2 bolts, fit some shims between MC and slave, like 1 mm thick, and test again. If this solves the issue, you need to check the clearance by removing the MC and measure (calculate) it.

Waldi

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Hi All

Just reading through this one and noted the supposed quality problems of master cylinders but current ones were ok. 

I'd heard the same about servo units.

So did i do the right thing by buying both new a few years ago as part of my resto.

Have i fitted cheap junk when i should have refurbed the old stuff?

One comment was they are ok now, so when were they ok from?

Cheers  Keith

 

 

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Hi Keith,

I think it depends on the individual item you have bought. If the vendor still had a bunch of suspect items and did not want to scrap these, you may have a poor one. 
On the other hand, if your items are in service for a couple of years, it is less likely you will have an issue (bath curve principle). 

Cheers,

Waldi

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3 hours ago, Waldi said:

Hi Austin,

have you checked the gap between the servo push rod and the cylinder piston? A simple test to increase the required clearance is to loosen the 2 bolts, fit some shims between MC and slave, like 1 mm thick, and test again. If this solves the issue, you need to check the clearance by removing the MC and measure (calculate) it.

Waldi

Hi Waldi, any idea what the clearance should be? The servo and master cylinder worked fine for several years.

Austin

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