Spongy brake pedal and brake light.

so as some of you may know, i recently did all new brake lines in my '95 rmw front to back and side to side. i rented a vacuum bleeder and bled both passenger side wheels successfully until the vacuum bleeder decided to take a sh**. so i got my dad to help me bleed the brakes the old school way. Managed to get all four corners done but the pedal still felt super spongy and didnt have much effect until depressed halfway down. brake light is still on also.

I know my rear shoes need to be adjusted out which would probably help raise the brake pedal up but im not sure why the brake light is still on. its my understanding that the brake light only comes on when the sensor on the proportioning valve notices a pressure difference between the front and back lines.

now, i did at one point have the master cylinder out of the car while doing the lines and it was empty. i didnt know at the time but i guess it's easier to bench bleed the M/C rather then have it mounted to the car. at any rate, i figured bleeding all four corners thoroughly like i did would have gotten rid of any air in the system.

one more thing, being the lines were so shot. its possible at some point between shuffling cars in my driveway that the brake pedal was applied with no fluid in the M/C.

any thoughts, suggestions

1. Air in the lines still.
2. Leaking rear wheel cylinder.
3. Loose fitting.
4. Broken line.

The rears should be self adjusting. Get in a parking lot, get it going in reverse around 20km, and jam the brakes as hard as you can. This will adjust the brakes if the stars aren't seized, and sometimes will reset the light.

As Jay said check the whole system over again to make sure you don't have any leaks. If it's all dry and there is still a possibility of air in the master cyl., take it off and bench bleed it. Then start back at the beginning and bleed everything again. It's the only way to be sure all the air is out of the system.

Mike

yea I should probably add i replaced the old wheel cylinders with new ones, rear brakes were disassembled and reinstalled. nothing appears to be leaking.


i thought applying the parking brake adjusted the shoes

thanks for the suggestions so far, ill go over everything again and bleed the system again. if no change i guess i'll pull the M/C and bench bleed it.


....cars

Check your ABS unit up front, it may have a small leak you are missing/not seeing. Had to replace the unit on the wifes car when we first got it.

In theory the rear drum brakes should adjust themselves when applying the brakes while traveling in reverse like Jay said. That doesn't usually happen unless everything in the drum is in very good shape. Pull the drums, and adjust the rear brakes until you have some slight drag of the drum on the shoes periodically for the best results. The parking brake adjusts the rear brakes on some rear disc cars, but not ours.

When I bleed brakes I use a mighty vac hand pump, I have much better results, and you can do it all by yourself.

I've had master cylinders give me a soft pedal after bleeding the brakes on older high mileage cars. Years of contamination, dirt, and what not collects in the m/c bore where the piston does not travel.... Until you bleed the brakes the old fashion way by putting the pedal to the floor.

Oh.... and if you have air in the master it may not build enough pressure to turn the brake light off.

Mike

Sounds to me like you might have air trapped in the MC. I would try bleeding that from the lines first. If that doesn't work then you might have to take it off the car and bench bleed it. Sometimes the angle of the MC when installed on the car prevents you from getting all the air out of it.

When you did the rear brakes, did you do all new hardware? The better combi kits include new star wheel adjusters that go at the bottom between the shoes. Those are what adjust the shoes when you brake in reverse. If not, it would be worth throwing a pair in (or, taking apart the old ones, freeing them up, lubing, reinstalling, adjusting, then setting them by braking in reverse). To simply adjust them (if they are working correctly), you don't have to go fast/brake hard in reverse like I told you to. That is for resetting the pressure switch in the prop valve after bleeding. Most times the light will go out once bled. Sometimes you need to do the super stomp in reverse. Speaking from experience as a guy that has replaced multiple brake lines on every winter car I have ever driven.

However, I still think you have air in there. Check the star wheels/adjustment first, though. If there is too much slack before the shoes touch the drum it would explain the spongyness (not the light, however). You could try a pressure bleeder from C Tire or Princess Auto.

Don't worry, you'll get it.

So... Update. Re-bled the brakes, adjusted the rear shoes out and the pedal feels normal but the damn brake light is still on. I double checked my ebrake pedal and its all the way up. I do however still have a busted ebrake cable but if the pedal is all the way in the released position I wouldn't think it would matter to the brake light. Any ideas?

Oh and jay, no I reused the old hardware. I took the adjusters out and cleaned them up and got them working as they should.
Haven't got a chance to do the reverse super stomp test. Thinking I should try that next...

Grab the release handle for the E brake. Put your left foot under the parking brake pedal and pull it up all the way to the top. I had one that the return spring wouldn't hold the pedal up high enough to turn off the light. I put an elastic band on it. Held the pedal in place, would break if I needed to use the pedal. I don't think this is your issue, though.

If you're confident all the air is out, do the backwards rolling super stomp. Works for me, hope it does for you. If that doesn't, get it on some gravel and brake hard enough to get the ABS going to cycle the fluid out of the pump. Two wheels on the shoulder, two on the pavement are good. Note that this is a really good way to end upside down in the ditch, please don't kill yourself. I'm giving this advice hoping that you are a good driver that is really familiar with how these cars handle.

Agree with Jason completely but I do believe that the busted emergeency brake cable is causing the system to think the ebrake is still on.Also when you spin the drums can you hear/feel the shoes just contacting the drums?I think until you get the ebrake working,the light will stay on.

The busted e brake has nothing to do with the light. The light is only illuminated by the pedal being depressed, or, a lack of balance in the hydraulic system. You could cut the e brake cables off at the drums, and as long as the pedal was all the way up, the light wouldn't come on.

I agree with everything Jay has said. I might add.... You may need to reset the brake light switch manually.
On the front of the combination valve (located just below the master cylinder) there is a rubber cap, press that firmly, that should reset your brake light switch. After all that work on the brake lines you did I would go drive it, get the ABS to activate, a few hard stops, then bleed the system again.

Mike

Thanks for all the input guys. Problem SOLVED. First thing I did was check the ebrake pedal to make sure it was fully up. Next I i did the rolling stomp. Still had the light' tried it again. Nothing. took it for a drive around town, brakes feel good, gas feels really good! but still had the light. Pulled into an empty parking lot and tried the backward rolling stomp once more and finally the light went out!! Thanks again for your help guys. I just finished both rear shocks. Getting ready for ebrake cable, water pump and rad replacement. Probably won't get done till I'm done college in a couple weeks.

Slowly but surely, the rescue mission on this car is almost done.

Great news, have fun driving it again.

Mike

I love it when the fix is easy like this one, and slamming the tail gate to make that light go out.

jayoldschool wrote:

I love it when the fix is easy like this one, and removing the gate ajar light to make that light go out.

Fixed.

I hate that light. It deserves a place in automotive hell.

Wait until you marry someone that has a VW.

That'd be grounds for divorce.

"I want a Beetle. It's so cute."

"I'M AUDI HERE."

lol, the Beetle was an upgrade from the Hyundai. At least she's into the Caddy ATS now...

One step at a time, right?