About to make a long post for a question as it’s quite the problem!
So finally got my l200s back on the road with an MOT but since have been plagued with an issue of sticky brakes. They get locked on and drag heavily or even make the car immobile. Seems to only be the front from a feel of heat in the wheels after a drive.
The front calipers have been rebuilt and seem good and when they look, with a release or a bleed nipples, fluid squirts out and the calipers free themselves seemingly on both sides. So clearly fluid is getting trapped pressurised. Seems to get far worse after I park the car (they relax again after a long time though). I’ve replaced the brake lines at the front with braided ones too now with no luck.
I’ve now gone back to the master cylinder and removed it. The piston end had clearly been leaking fluid (crystallised brake fluid had formed) and upon dismantling, the sealing o ring looked not ideal but looked all good otherwise which was disappointing.
At this point still uncertain on the issue, I took the brake booster off as it had paint damaged from brake fluid so may be compromised inside. Upon testing it out of the car with vacuum attached, it became no easier to press which is a bad sign usually and then checked my l500 booster that looks brand new from a 28k mile car but that also didn’t get any easier to press with vacuum.
The piston on the l200 brake booster I noticed poked out some and I am unsure if this is normal or if the fact they are missing check valves or if they should get easier with vacuum (literally there purpose but I’m shocked both are bad) and I’m now lost on the situation.
silly basic question and Im sure you made sure but is there any vaccum leaks in the hose from the manifold to the intake manifold? Is there a block in the intake connector on the manifold?
I have not checked so will probably check that today, I have been curious to check the vacuum out as I noticed when I put my thumb over the brake booster hose, it does pull a vacuum but if I hold my thumb there it actually stalls the engine. I feel like that’s not right so I want to check other vacuum lines. I might check all the vacuum lines on the engine.
Further update, testing some bits out with the vacuum. Blocking the brake booster hose doesn’t stall the engine. It just idles so high without it blocked that when you block it, it revs down so much it sounds like it’ll stall. It doesn’t tho and gains a really smooth idle. Found the vacuum hose that goes from the intake to the valve cover was pretty perished so replaced that but otherwise all looks good. I do have a vacuum hose I am curious about. Very little air travels through it and I’m guessing it’s the crank case ventilation. It’s those hose photographed:
It connects to the airbox and then goes down the back some. Would explain why the inside of the airbox always looks a little wet if it is the breather.
yeh that big hoss is a crank case breather. I usally get a catch can and put that one to the catch can and als the rocker cover one to the catch can or to the airbox. If you leave the rocker cover one attached to the intake and your car starts blowing smoke then move it to the airbox or catch can.
I don’t have any other Ideas on the brakes but is the car manual or auto?
The car is a manual. I think I’ll finish the master cylinder seal replacement. Refit the brake booster and and give that a go. If that doesn’t work. I’ll order all new parts except the brake booster.
I haven’t got symptoms of a bad booster but when both are connected to vacuum, neither change in difficulty which would usually indicate they’re bad but neither are difficult to press and I’d be shocked if the l500 was bad as it’s mint with only 28k miles on.
To update this situation, after some investigation, I found that the brake booster was mounted, as the nuts tightened the booster down, it actually caused the booster to engage due to the only mountable adjustment on the brake pedal. This meant it had the booster pushrod engaged by 3mm at all time. This might be the cause of my problem and hopefully resolves. It to help this I’ve had to cut some of the pedal mounting threads and I’ve 3D printed a 10mm spacer to space the booster from the firewall. I’ll likely adjust this more as the closer I can get the booster to the firewall, the better.
