Remove ABS

[EpicRasta]

Ok, so i've been having hella problems with my Yukon and the brakes. everytime i get it fixed it seems to be another problem that arises. This is wha ti've replaced so far:

both front calipers
both front rotors
both front pads
both front brake lines
wheel cylinder
master cyclinder (twice)
abs pump

INitially, the brakes were locking up and i didn't know that the previous owner pulled the ABS light from the dash. The abs pump/ecu was throwing 13 codes, Thus, i had to replace it. Everything was better until it locked again....disocvered it was a rusted backing plate, creating play when the brakes were applyed causing the wheel cylinder to pop out and not return to its resting position. THe place i took it to bled the abs pump too.

Now, i just replaced the master cylinder again because the pedal is too mushy and when i press the brakes the brake light came on. Bench bled the master cylinder, Bled the system, was a hair better, but now the spongy brakes are back again and the light is back on.

No drips, no leaks (that i can see)...no idea.

One thing i did notice, however, is that I put brand new fluid in he entire system...bled out all the old fluid. But now the fluid is extremely dirty...

Could this be a bad brake booster?? Thats the ONLY thing that hasn't been replaced

My thoughts is tha ti wanna get rid of this entire abs system...can it be done??

 

[nimrodcs]

Do you have any aftermarket mods to your engine? Maybe raising compression? From what I understand, engines with higher compression do not produce enough vacuum for all the systems that require it, including your brake booster.

Hence, why some people convert their systems to hydroboost braking. This uses hydraulic pressure from your power steering pump to control your brakes, of course, providing way more power than your stock vacuum power booster.

Another thing, I think it says in the manual that after servicing rear drum brakes (dont know your year) u should accelerate backwards kinda fast and then hit your brake pedal to set them correctly. Just a thought.......

Not sure about removing the entire ABS system though.

 

[EpicRasta]

Do you have any aftermarket mods to your engine? Maybe raising compression? From what I understand, engines with higher compression do not produce enough vacuum for all the systems that require it, including your brake booster.

Hence, why some people convert their systems to hydroboost braking. This uses hydraulic pressure from your power steering pump to control your brakes, of course, providing way more power than your stock vacuum power booster.

Another thing, I think it says in the manual that after servicing rear drum brakes (dont know your year) u should accelerate backwards kinda fast and then hit your brake pedal to set them correctly. Just a thought.......

Not sure about removing the entire ABS system though.

hmmm, i'm glad you've explained the hydroboost conversion. I honestly never really understood it completely. Does it effectively remove the brake booster from the equation??

Also, i thought if the brake booster goes bad, the brakes get super hard.....and NOT super spongy?? please correct me if i'm wrong.

FInally, i'll try the stopping in reverse method in about 50 minutes. when i get off work.

---------- Post added at 04:20 PM ---------- Previous post was at 04:15 PM ----------

Do you have any aftermarket mods to your engine? Maybe raising compression? From what I understand, engines with higher compression do not produce enough vacuum for all the systems that require it, including your brake booster.

Hence, why some people convert their systems to hydroboost braking. This uses hydraulic pressure from your power steering pump to control your brakes, of course, providing way more power than your stock vacuum power booster.

Another thing, I think it says in the manual that after servicing rear drum brakes (dont know your year) u should accelerate backwards kinda fast and then hit your brake pedal to set them correctly. Just a thought.......

Not sure about removing the entire ABS system though.

oh i forgot to add that i have absolutely no engine mods, well other than an intake...but that doesn't count LOL

 

[nimrodcs]

Does it effectively remove the brake booster from the equation??

Also, i thought if the brake booster goes bad, the brakes get super hard.....and NOT super spongy?? please correct me if i'm wrong.

Yes, hydroboost does remove the booster from the braking system. I'm pretty sure you have to have an adapter plate fabricated to mount the hydroboost reservoir to your firewall. Then run high pressure lines from your power steering pump and steering gear box. I'm not sure the exact procedure. There is more about the conversion in this thread from Whippled2dr:

http://www.tahoeyukonforum.com/forum/showthread.php?t=1408&highlight=hydroboost

You are right about the brakes being hard if the booster goes out. All I can say is that your still getting air in the lines from somewhere. Air is what causes the spongey feeling 90% of the time. I too, have the spongey feeling in my brakes a little, but just decided to live with it until I convert to hydroboost.

 

[THE-HOE]

Oh boy, I feel your pain. I had so many problems with my ABS i just disabled it completely. Which is easy as crap. Just pull all the abs fuses/relays or whatever. I did it on mine and never had problems again, it changed absolutely nothing about the feel of the breaks, just doesn't have abs now. Hope this helps!

 

[99chevy2dr]

I had the same problem with the brake light and soft pedal.. put new rear drums, shoes, wheel cylinders, bleed them and problem went away.....

Good Luck!!!!

 

[EpicRasta]

Thanx guys.... I know THE-HOE says that he just removed the fuse/relays, but did you do this on a pre-1999 truck? On the pre-1999 trucks, our abs units are hydrolic. THe problem with them is that the proportioning valves are actually built into the unit itself. Thus, there could be a leak in it somewhere causing all kinda mayhem.

Thus, i'm trying to figure out how to get rid of it all together. Maybe i'll try the hydroboost thing first and see. Is anyone good with brakes around here in Illinois??? LOL

 

[loulblades]

...
Thus, i'm trying to figure out how to get rid of it all together. Maybe i'll try the hydroboost thing first and see. Is anyone good with brakes around here in Illinois??? LOL

Are you saying you want to get rid of the ABS system? If so that is what I did but you may need to put in a proportioning valve. I got one from Summit that is adjustable so I could throw some extra bias to the rear brakes when I get around to replacing the drums with discs.

 

[EpicRasta]

Are you saying you want to get rid of the ABS system? If so that is what I did but you may need to put in a proportioning valve. I got one from Summit that is adjustable so I could throw some extra bias to the rear brakes when I get around to replacing the drums with discs.

NICE! yeah, i know i'm gonna have to put a proportioning valve in there. how did you do it?? did you do a write up on it?? have any othe rpeople done this b4?? i really don't see a real advantage to having ABS anyway...i dunno, i mean i see a point with it, but brakes still work without it 2.

 

[loulblades]

I never did a write up but here's what I did.

1. Ripped out the EBCM and tied off the wires (might remove them someday)

2. Made/installed a small mounting bracket for the valve.

3. Bought some short brake line to connect the proportioning valve to the master cylinder and installed some new lines from the valve to the front and some new lines to the first fitting going to the rear.

3. Bled the system.

4. Adjusted the valve until just before the rear wheels locked when I slammed on the brakes on a dry road. (lot of try/adjust)

The area where the EBCM was located gave me some space to install a distribution panel from my 2nd battery.