April 18, 2019, 02:34:05 PM

Author Topic: ABS/brake issue  (Read 2570 times)

Offline Gunnytron

ABS/brake issue
« on: February 18, 2018, 11:38:32 AM »
I haven't used the car for a while now. The last time I went to take it out, the brakes wee a bit dodgy. The car still stopped but you could feel the ABS fluctuating and the pedal sort of vibrates under foot (like what I imagine ABS to feel like) and feels very light.

After last time this happened, I bled the brakes again, then left the car sat for several months.

Today when I took it out, the strange pedal feel is back.

I can't see any signs of leaks so has anybody else experienced this sort of thing?

FYI I do still have ABS and I use speedbleeder brake nipples.

Ta
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Supe

Re: ABS/brake issue
« Reply #1 on: February 18, 2018, 02:39:14 PM »
What did the fluid look like when you bled?  I had similar issues, and all the seals in the ABS unit deteriorated.  I had bits of rubber in the whole system.

Offline Gunnytron

Re: ABS/brake issue
« Reply #2 on: February 18, 2018, 05:33:10 PM »
I don't recall actually. I will bleed them.again and take note.

Can you service the seals or do you have to get a replacement?
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Gunnytron

Re: ABS/brake issue
« Reply #3 on: February 19, 2018, 04:04:53 AM »
I did read a thread that says you should have the ignition on before you bleed the brakes. Not sure how true that is or if it applies to the later spec ABS pumps.
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Skeltic

Re: ABS/brake issue
« Reply #4 on: February 19, 2018, 11:39:41 AM »
remove and carefully clean your abs sensors the mount area and the mounting bolt
"You can sleep in your car, but you can't race your house."

Offline Gunnytron

Re: ABS/brake issue
« Reply #5 on: February 19, 2018, 12:52:37 PM »
remove and carefully clean your abs sensors the mount area and the mounting bolt

They are all pretty mint. Unless I damaged any, but then I would expect an abs warning light.
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Skeltic

Re: ABS/brake issue
« Reply #6 on: February 19, 2018, 01:16:17 PM »
I have had the luxury of seeing the live data plot of the sensors since I have a race logic installed. You wouldn't believe how bad your sensor signal can be and not throw a code.
"You can sleep in your car, but you can't race your house."

Offline Gunnytron

Re: ABS/brake issue
« Reply #7 on: February 19, 2018, 04:31:43 PM »
I have had the luxury of seeing the live data plot of the sensors since I have a race logic installed. You wouldn't believe how bad your sensor signal can be and not throw a code.

Oh really? OK, I will get the meter on them.
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Gunnytron

Re: ABS/brake issue
« Reply #8 on: February 24, 2018, 12:47:21 PM »
So I jacked the car up and checked all the brakeline junctions and they are bone dry.
I also tested the resistance of all the sensors and they were all good.

Bled the brakes again and the fluid is all clear. There was a little sediment in the jar I used last time, but no black debris.

I've not had a chance to take it out yet. Hopefully tomorrow.
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Skeltic

Re: ABS/brake issue
« Reply #9 on: February 24, 2018, 10:03:34 PM »
take the sensors off and clean the mounting surfaces, be as thorough as possible that is where I got my biggest gains getting the sensors to  work better
"You can sleep in your car, but you can't race your house."

Offline Gunnytron

Re: ABS/brake issue
« Reply #10 on: April 02, 2018, 11:25:23 AM »
I jacked up the rear of the car today and ran it on the axle stands. After a little while my ABS light started to come on. It only appeared to come on once the wheels were spinning (coincidence?).

By my logic, that would mean the issue could be with the rear sensors.

I thought I read somewhere that with the newer ABS units you could get error codes from the warning light. This true?

Here's a pic of one of the sensors. Doesn't look too bad to me?
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Drsnoopy

Re: ABS/brake issue
« Reply #11 on: April 02, 2018, 01:31:37 PM »
The ABS light might have also illuminated while it was running on jack stands due to only 2 of the 4 wheels spinning. I know ABS systems usually use the speed of all 4 wheels as a input so it may be possible it set a trouble when only two wheels where spinnining making it seem to the abs module that the front two were at full lock.

Offline Drsnoopy

Re: ABS/brake issue
« Reply #12 on: April 02, 2018, 01:33:07 PM »
Could it be just the corrosion build up on the face of your rotors from the car sitting causing you to feel a slight pulsation? Does it go away after a brake engagements?

Offline Gunnytron

Re: ABS/brake issue
« Reply #13 on: April 02, 2018, 04:08:44 PM »
The ABS light might have also illuminated while it was running on jack stands due to only 2 of the 4 wheels spinning. I know ABS systems usually use the speed of all 4 wheels as a input so it may be possible it set a trouble when only two wheels where spinnining making it seem to the abs module that the front two were at full lock.

So does the ABS light come on when you do burnouts?
http://www.norotors.com/index.php?topic=12880.0
FD, LS1 running 220 3.90 Trickflow heads, Comp Ultra-gold Arc 1.72 Rockers, 7.550 BTR Pushrods, BTR Stage II NA Cam 227/234 .614"/.576" 113+2, ARP Head Bolts, BTR Platinum Springs, Ported FAST 90, NW 90mm TB, FAST 60lb Injectors, Textralia Clutch/Flywheel, T56, Cobra 3.55 Diff, Holley HP EFI, Racelogic TC.

Offline Drsnoopy

Re: ABS/brake issue
« Reply #14 on: April 02, 2018, 04:42:02 PM »
The ABS light might have also illuminated while it was running on jack stands due to only 2 of the 4 wheels spinning. I know ABS systems usually use the speed of all 4 wheels as a input so it may be possible it set a trouble when only two wheels where spinnining making it seem to the abs module that the front two were at full lock.

So does the ABS light come on when you do burnouts?

Now that you mention it, I never thought about that. I have however witnessed abs light flash/ abs valve actuation if the brakes are used trying to decel a car running on a dyno.