No pressure on front brakes.

P

Preben

New Member
I´m working on my 3500 ´74 which has been standing over many years, the brake fluids were impossible to describe (yak) and the pistons in the front calipers are stuck. Now i´ve cleaned both reservoirs and have brake fluid to the slave cylinder, but nothing to the front wheels. I have no fluid to the line in the rear on the slave cylinder, the one with a big plug and plastic valve in it.
What can be wrong, the slave cylinder?
If it´s the slave cylinder is it possible to overhaul it or is it a sealed unit with the servo?
 
Hello Preben,

The booster slave cylinder can be removed completely from the vacuum chamber, dismantled, resleeved in stainless steel if it has not already been done, fitted with a new seal kit and refitted.

When you say that you have no brake fluid to the front calipers,..when you depress the brake pedal while your trusty helper opens the bleed screw on either caliper, attached to which is a length of clear hose which ends in a glass jar filled partly with some brake fluid, does no fluid exit the caliper?

Brake fluid is hydroscopic, so needs to be changed at least every 3 years in order to prevent at the very least corrosion from taking place within the system. The brake fluid boiling point is also lowered with moisture absorbtion.

Ron.
 
There was all kinds of shit in the brake fluid, the car has been standing for more than 10 years, and the in one of the reservoirs had "melted" in the brake fluid. I saw no bolts or änything att the slave cylinder/servo, and my useless manual does not mention it att all. I have no trusty helper, i´m doing it by myself and using a pressure powered brake bleeder. When i take the brake line to the front brake loose an press the pedal, it should squirt from the hole, but it does`nt
 
If it's been stood for 10 years I would say you have no option but to replace and refurbish the whole lot. I did mine a few years ago when I rebuilt my engine. You can do the pipes in a day.
Wins international do reconditioned servos for around £130 and don't require an exchange. There are plenty for brake pipe sets on eBay and the service kits for the front and rears are cheap enough along with the flex pipes from JRW. I'm sure they would post to Sweden.
 
You need to remove strip and rebuild,or replace both your calipers,as I suspect there is more shit in them stopping the fluid flowing!
Sometimes pedal pressure will be enough to free them,but when they get really stuck then you have no option but to rebuild them or replace them,as your life will depend on it!
 
What sort of brake fluid are you using? Some of the dot 5 fluids, and silicone fluids will cause the rubber seals to swell. The best stuff to use is Castrol LMA, which was recommended for girling brake systems. Silicone brake fluids cause the natural rubber seals to swell. Have you taken out the bleed nipples, and checked that they are not blocked full of crap? Are you bleeding with the motor running, or not? I got a car back on the road which had sat for 10 years, and all I did was bleed the system to get out the dirty fluid. One of the pistons weeps just a touch, and I will fix that up some time. My other Rover 2000 has the original seals in it from when it left the factory back in 1969.

James.
 
I have no idea what brake fluid was in it as i cleaned the reservoirs. The reason that i would fix the hydraulic system now, was that i would try to get out the pistons in front callipers, as they are stuck, i tried with air pressure, but that did not work. Maybe a grease nipple and grease (instead of the bleeding nipple) will do the job.
I guess i will have to rebuild the slave cylinder as i suspect that is seized up inside, no fluid out of the slave cylinder is no fluid att the wheels.
 
I agree with the others here. A recurring issue with P6 brakes are rubber (flexi and even vacuum) hoses that collapse and clog up internally. Your system sounds ready for an overhaul, which is inexpensive parts-wise and extremely satisfying to have completed. Not too difficult, not much need for special tools, but messy! Having never touched such a job before I did it all myself, but needed pressurised air like you do to pop one or two of the front caliper pistons. All the correct parts were readily available, even for the dual circuit system, but if ordering a brake servo or other parts from the UK be sure to specify that it must be dual-circuit (which yours is, judging by your mention of two reservoirs). I think I spent around £100 on all the seals kits (four calipers, master and slave cylinders with booster) and new braided flexi hoses all round.
 
Tor said:
I think I spent around £100 on all the seals kits (four calipers, master and slave cylinders with booster) and new braided flexi hoses all round.
Click to expand...
Where did you buy seals for the booster/slave cylinder? I´ve been looking on ebay and Rover classics, but did not find anything for the slave cylinder.
 
I think Pierre at Rover Parts Services was my source at the time. The kit included the rubber septum (bälgen) for the servo and some fitting instructions. I'll PM you the details :)

Regards,

Tor
 
Preben said:
Tor said:
I think I spent around £100 on all the seals kits (four calipers, master and slave cylinders with booster) and new braided flexi hoses all round.
Click to expand...
Where did you buy seals for the booster/slave cylinder? I´ve been looking on ebay and Rover classics, but did not find anything for the slave cylinder.
Click to expand...

www.jrwadhams.co.uk

They have been doing P6 parts for years, you can't go wrong although some of thier parts can be on the expensive side (but a lot of other stuff is well priced). They should have everything you can't find else where.
 
Hello again!

I´m now overhauling the slave cylinder, i´m sure that i hav memorized it correct, but now i have my doubts. :?

I have fitted the seals on the piston in the bottom of the cylinder, but it looks wrong. :( The seal nearest the spring has the lip pointing toward the spring, but on the seal in the other end is pointing in the opposite direction. Is this really correct?
 
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