Uneven braking power rear Golf 3 '95 TDK

[$hitblast]

I took it to the bi-annual checkup that is required in Norway. There was lots to fix, and it all got fixed, but this one problem still stands: The rear brakes brake equally strong at first. Then the left side doesn't get any stronger, and the right side continues normally, to about 40% more than the left side.

I've changed both cylinders and shoes, greased the contact points on the back plate, and washed the drums thoroughly with de-greaser, but there is no change.

Any ideas?

[h100vw]

I took it to the bi-annual checkup that is required in Norway. There was lots to fix, and it all got fixed, but this one problem still stands: The rear brakes brake equally strong at first. Then the left side doesn't get any stronger, and the right side continues normally, to about 40% more than the left side.

I've changed both cylinders and shoes, greased the contact points on the back plate, and washed the drums thoroughly with de-greaser, but there is no change.

Any ideas?

Bled the cylinders properly?

Have the shoes adjusted up evenly?

Handbrake cable/s (not sure there's 2 or not) adjusted up correctly

[$hitblast]

h100vw: I got the same error two years ago, on the checkup then, but the guy looked through his fingers with it. Since then, I've taken the rear braking system completely apart twice, and put it back together again, with new shoes and cylinders the last time, and I still get the same error. It's had it's brakes tested five times the last three months. I've made changes to the brakes in between the test, including bleeding. Before the last checkup, there were eleven consecutive squirts with no bubbles at the end of the bleed. To me it seems that air in the system would make a difference from the getgo of the test, and not so suddenly, at the same inflection point and side each time, having been bled on both side in between measurements.

[h100vw]

swapped drums side to side?

[$hitblast]

h100vw: No, I haven't. I've ground off the edges, though. The system works symmetrically fine up till 3 kN, but then starts to differ. A drum can't decide to give less friction when something is pressed harder against it, but the pressing-mechanism may fail. Do you know if the main cylinder or brake load valve can cause asymmetric braking?

[h100vw]

If the shoes don't match the drums, braking can be weak. Like when you fit new pads to front discs that are not new or machined flat. New shoes sat on top of ridges.

UNless there's a blockage I wouldn't expect the MC to give you a problem. Not sure about the load valve failing internally. I haven't worked on anything with drums since 1995.

[$hitblast]

So, I've read up on proportioning valves in relation. My Golf has ABS with disks in front. Does it have a proportioning valve?

[h100vw]

So, I've read up on proportioning valves in relation. My Golf has ABS with disks in front. Does it have a proportioning valve?

No idea, stick your head under the back. I can imagine that it wouldn't need one though. as the ABS would provide the same result

[$hitblast]

Yea, I figure I have one. I just did new lines on it, and hooked them up to what I thought was only a load-regulator. Here it is:





Edit: It looks like maybe someone has been meddling with it, since it seems to perhaps be missing a bolt.

In addition to regulating the load, does it also do the 20/80 proportioning job?

[dylan8]

If the car has ABS have you tried triggering the ABS pump while bleeding?

[$hitblast]

No, I haven't. I didn't know the option existed. I have a cheap cable that I've used to delete codes before. I'm not sure if it will do that job. What will this test tell me? In any case, the ABS system seems to work fine. Norway's a slippery place half the year. I did a full power stop from 80 km/h to standstill with a quite wet surface a couple of weeks ago, and that worked well. Do you know if rear wheels can be controlled separately by the ABS?

Edit: ..since there are two lines going aft to the load sensing valve. If not, what would be the reason for double lines to the rear?

[$hitblast]

So, since I have two aft brake-lines, going to each their wheel, I figured I'd try and switch them before the load-sensing valve, to determine whether the problem is in front of it, or including it and everything behind. This had no effect on the brake-test, so I figure the problem is with the load-sensing valve or something further back.

Here's today's test.


The load-sensing valve has a broken bolt in it, and is fastened with an unoriginal bolt. The piston compressor hinge is quite rusted, so I assume this part came from another vehicle when installed. Since I've done reasonably due diligence to its periphery, it seems worth the try to install a new load sensing valve.

[$hitblast]

Does the load sensing valve need to be specified for ABS or drums, or will anything with OEM numbers 1H0612151, 1H0612151D or 1H0612151F work?