24 replies to this topic

[icrocky]

Hi I have a 1969 mini countryman mk2.

I've just tried to bleed the brakes. Front brakes bled fine, the rear brakes I couldn't draw or push any fluid through, I even removed the brake valve, still no fluid. When pushing the brake pedal with the valve out the pedal still has resistance and doesn't go to the floor.

I'm thinking it might be the pressure regulator valve, which I think is located on the rear subframe.

Can anyone confirm my diagnosis and provide any tips to replace it please?

[bpirie1000]

What kind of master cylinder have you got?

Also start at the start of the rear pipework and crack each join and test until you find where the issue is..

Could also try a gunsons bleed kit. Takes pressure from a spare wheel and pushes the brake fluid through the system..

Also how old is the brake fluid. Could be a contaminant in there certainly think the bias would be the issues though..

[Ethel]

Are you saying you got a hard pedal from bleeding the front?

 

If they are new lines it'd take some effort (plus topping up the reservoir) to pump fluid through with the pedal.

[icrocky]

Hi. The master cylinder is a standard metal one with plastic cap.

I'm bringing the car back to life, having been off the road for 30 years. So I'm replacing fluid, brake shoes etc.

I started bleeding them with the hand held vacuum pump. This worked ok on the front brakes. I tried the same method on the rear and could draw no fluid. I then reverted to the 2 man method with mu partner pumping the brake pedal.

I have seen other threads which suggest that pumping the brake may have closed the valve.

[icrocky]

Hi. No I mean with the bleed valve open the pedal seems normal - I think its only operating the front brakes. Sorry for any confusion

[Ethel]

It would be faulty if it stayed closed.

[icrocky]

Hi Ethel. Do you mean the regulator is faulty if it remains closed?

[Ethel]

Yes,

 

but that's assuming it's the standard one on the rear subframe and that it is actually staying shut and not shutting every time because you jumped on the pedal.

 

I find pulling fluid through less problematic. All you need is a syringe & a bit of  hose to connect  it to the bleed nipple.

[icrocky]

Ethel, if it's because I jumped on the pedal, how do I clear it?

[Ethel]

Don't think I've been clear enough again...

 

There's a spring inside to control the pressure required to shut it. It will also open the valve when the pressure from pressing the pedal is released.

 

I meant it could be closing every time, if you hit the pedal too fast & hard.

 

 

.... it's just registered you used a vacuum pump. Did you get the sense it was creating a vacuum on the rear?

[cal844]

Crack the unions and pump the pedal to chase the air along the rear pipes, do this with the rear bleed nipples open

[icrocky]

Ethel, the vacuum pump has a gauge that showed a vacuum was being created. Once the vacuum is created the bleed valve is opened. The vacuum then disapates. But no fluid is drawn.

The process went well on the front brakes

[Ethel]

It could be the way to go. but if you do it by pumping the pedal it'll pull the fluid back when you lift you  foot up unless it's sealed against atmospheric pressure.

 

 

I'd stick with the vacuum pump.

 

If you hold the pedal down it'll isolate the reservoir, so you should be able to create vacuum in the line with the pump. If you then let the pedal up it should drawer fluid in until the vacuum is filled. That would tell you there is no blockage, even if no fluid emerges,

[icrocky]

I think I shall buy a new valve tomorrow and also crack the unions as Cal has suggested.

I will bleed the brakes the old fashioned way. My partner will be thrilled!

Thanks to everyone for their comments. I'll update when I've done the above.

[cal844]

I think I shall buy a new valve tomorrow and also crack the unions as Cal has suggested.

I will bleed the brakes the old fashioned way. My partner will be thrilled!

Thanks to everyone for their comments. I'll update when I've done the above.

Try my method first before you buy any parts