Brake and clutch issues for the new racer platform

[SharkSkin]

Originally Posted by mark kibort

ok, got it.

So,i was looking at it a little closer today, and it seems there are only 2 lines connected to the master. the rear most located (front brakes) and the and the front located connection (rear brakes). so, at the ABS, there are a bunch of connections. you want me to disconnect the front brake line as it exits the ABS unit. The main line from the master seems to connnect to the bottom rear of the ABS unit. You are saying that since I was able to push fluid out on the passenger side, then, its kind of like the master is working fine. it really has to be in the driver side lines or ABS system side to side splitter system internal to the ABS.

keep that ABS controller warm for me. I bet that is the problem, as I have a hard time believing that a line could be clogged like this.

mk

.

Yep, has to be the lines or the ABS unit -- but don't just throw parts at it! I have never seen a brake line clogged that bad either, but check it anyway. Diagnosis 101 -- eliminate possibilities, even if they don't make sense. It could have been pinched during all of the excitement, and it would suck to R&R the ABS unit and find that you still have the same problem.

[mark kibort]

I did that. the one side seeped fluid with the pressure bleader on, and the driver side did nothing. pushing the pedal,it actually pumped up a bit, and when I pushed REAL hard, it gave way and some fluid came out. I then, pumped the pedal and fluid came out with each press. then, the next time i did this, nothing came out, and even a firm press on the pedal, yielded nothing to the driver side line(before the caliper. something is clogged and from the sounds of it, it has to be the lines or the ABS cross over internal, as Dave says.
I guess thats an easy check. Ill pull the front driver line from the abs and see I can blow the line free, or if somethingcomes out of the ABS unit at the output hole.

I guess the next step if something is blocking internal to the ABS system, could be to blow compressed air to the front inlet to the ABS , with the one side line disconnected. it all sounds pretty screwy right now.

mk

Originally Posted by FlyingDog

Is your clutch blue hose clamped on? If so you should have no problem running the pressure on the power bleeder up to 20-25psi. IIRC, 25 is the stated limit for the bleeder. Only open one line at a time. If the system has lots of air in it, sometimes the power bleeder will just keep compressing the air without really pushing much fluid. Keep the bleeder hooked up and pressurized while pumping the pedal.

[atb]

Mark,
I had a very similar situation with my OB track car, only it was the passenger front that wouldn't pass any fluid, all three others did. Like you, with the power bleeder pumped to 10psi, I push on the brake pedal with the three other calipers closed and the bleed port on the passenger front open. Pedal was hard, but then released with gush of fluid out the bleed port. This was with the stock OB calipers. Worked fine for an 8 hour track day with a 10 hour round trip. Switched to S4 calipers all the way around, and did the same track event again. Have never had any issues.

[mark kibort]

sounds similar, but im doing the test with no caliper attached.

maybe that same type of clog is in the ABS unit. I guess it has to be.
anyway of cycling the aBS unit without starting the car?? I have no idea what that means. the most ive ever done with abs has been replace a relay.

mk

Originally Posted by atb

Mark,
I had a very similar situation with my OB track car, only it was the passenger front that wouldn't pass any fluid, all three others did. Like you, with the power bleeder pumped to 10psi, I push on the brake pedal with the three other calipers closed and the bleed port on the passenger front open. Pedal was hard, but then released with gush of fluid out the bleed port. This was with the stock OB calipers. Worked fine for an 8 hour track day with a 10 hour round trip. Switched to S4 calipers all the way around, and did the same track event again. Have never had any issues.

[SharkSkin]

Mark, I have a tool that can cycle the ABS valves and pump but all of the wiring has to be in place and in working condition.

[mark kibort]

all the wiring is attached, except for the LH/EZK, and the individual sensors, but that is a 5 min job as everything is ready to plug in.

maybe I can have lunch here some weekend day, test it out, and we can see if that does anything.

Thanks!

Mark

Originally Posted by SharkSkin

Mark, I have a tool that can cycle the ABS valves and pump but all of the wiring has to be in place and in working condition.

[SharkSkin]

Mark, any updates? Have you checked for blockage in that line?

[mark kibort]

just finished checking the line. it is free as a bird on the line to the driver front. i pulled off the rears, they get fluid pumping out the bleed line. the passenger too. only the driver front is an issue and the pedal is really soft, but pumps up a little, but, still nothing, not a drop, comes out the driver side line.

i think Ill have to take you up on the ABS unit, unless you have any other ideas.

mk

Originally Posted by SharkSkin

Mark, any updates? Have you checked for blockage in that line?

[Mrmerlin]

Mark did you verify that the DS line from the ABS to the wheel is clear?? you can blow through it after disconnecting it from the ABS unit.
Also i would suggest that wait till you can power the car before you replace the ABS unit I have not heard of any ABS units failing, it may just need to be powered and then the line may open if it is in fact the ABS unit causing the problem.
First remove the line from the ABS and blow through it, it seems to me that it may have gotten pinched closed

[mark kibort]

Yes, I removed the line, as it is the easiest to get at at the ABS unit, and i was going to blow it out with compressed air, but just blew into it like I was blowing up a balloon. free and clear. no restriction. I was thinking of ways to get air blown into the ABS unit, but thinking of how much pressure the master cylinder puts, it wouldnt do much, i thought. so, I cracked a rear line and pushed the pedal and it bled and forced fluid normally.

how does that ABS unit power up? to test? something on the relays on top of the ABS unit that I can tap into with 12v?? Ive already powered things up, but not with the ECUs attached.

mk

Originally Posted by Mrmerlin

Mark did you verify that the DS line from the ABS to the wheel is clear?? you can blow through it after disconnecting it from the ABS unit.
Also i would suggest that wait till you can power the car before you replace the ABS unit I have not heard of any ABS units failing, it may just need to be powered and then the line may open if it is in fact the ABS unit causing the problem.
First remove the line from the ABS and blow through it, it seems to me that it may have gotten pinched closed

[SharkSkin]

Originally Posted by mark kibort

how does that ABS unit power up? to test? something on the relays on top of the ABS unit that I can tap into with 12v?? Ive already powered things up, but not with the ECUs attached.

mk

It's complicated. I have a tool that I made to try and help Nicole, which cycles the solenoids individually and can cycle the pump. For one of the solenoids to be blocking that line, it has to be stuck in the "activated" position. Even if we could jog it free I'd be worried that it would stick again. We can give it a try if you'd like, maybe Saturday?

[mark kibort]

Sounds great. Sunday may work better, but im sure I could find an hour in the late am to give it a shot if you have some free time. the interesting thing is, originally, i was able to get a little fluid out of that side. remember, it was going out slowly, but the pedal was stopping near the bottom and then with a big push, it fired out of line and I was able to continue bleeding, almost normally. Then, the next time I went to that side to bleed it, nothing. nothing with the pressure bleeder and nothing with the pumping of the master. If there is a valve internally, something might have caused it to close or maybe it was partially closed before the car had its power supply removed?
I have about 3 big cans of brake fluid on its way, so Ill get all the old stuff out, as it seems most of it is out now.

Now, im wondering what the deal is with the clutch it feels real soft and spongy, but it does work the clutch to roll the car back in gear. maybe it just has some air in the line now. I guess I can push the shaft back in the slave and see if that changes anything. I hope it doesnt need a master, but you know I have the Dremmel handy! (for that inside fender area)

mk

Originally Posted by SharkSkin

It's complicated. I have a tool that I made to try and help Nicole, which cycles the solenoids individually and can cycle the pump. For one of the solenoids to be blocking that line, it has to be stuck in the "activated" position. Even if we could jog it free I'd be worried that it would stick again. We can give it a try if you'd like, maybe Saturday?

[SharkSkin]

I have other plans on Sunday... The solenoids are spring loaded so if you lose power to the ABS the brakes still work. I think the clutch hydraulics are easier to service as a unit...no cutting required.

[mark kibort]

so, im thinking one of the solinoids are stuck. is there a motor on the back that turns a cam that opens the solinoids when the ABS gets the signal? I have no experience here and all i know is that driver path, in the ABS unit is clogged or something has been closed off.

Saturday will work if its before lunch. (or around lunch time)

as far as the clutch hydralics, i guess, remove the 2 nuts at the clutch pedal and it all falls out just where you can see the line input on the clutch master below the vacuum booster? I guess you might be able to get a hand in there to put it back in the hole, even though its semi blind. hopefully, the clutch master is still ok and just needs to be bled better.

mk

Originally Posted by SharkSkin

I have other plans on Sunday... The solenoids are spring loaded so if you lose power to the ABS the brakes still work. I think the clutch hydraulics are easier to service as a unit...no cutting required.

[SharkSkin]

The PDF that I mentioned above has a nice schematic of the ABS unit. The solenoids are just that -- they directly act on the shuttle valves that first block off pressure from the MC to the caliper, then as the current to the solenoid increases a passage is opened that allows the ABS pump to relieve pressure on the caliper. The problem here seems to bee that the DS solenoid is not returning fully to its "at rest" position.

I can be there by 11:30 or so Sat.

Do you have a loose battery? If you do we can use that to bypass the car's electrical system so we are working with just the ABS unit. I'll bring my control box and the spare pump.