I can't seem to find a suburban forum on the net so I was hoping you all could help me. Our 97 Sub with 117K miles has a brake problem. The brakes work fine till that last two feet when you're almost stopped and then it seems like the anti-loc brakes kick in. It makes the wirlly sound and I lose braking till I push harder on the pedal. It does this every other time I stop and is getting scary. I guess I'll take it in soon but am wondering what you all might think is wrong with it.

thanks

Don't know what your problem is but I wouldn't waste time getting it checked................

The front wheel speed sensor have too much rust and crap on them. Clean them and where they mount and that should clear up the problem. What happens is they are unable to sense wheel speed properly and drop out too soon causing the abs module to think the wheels are skidding.

Very common problem. Can go one of two ways on the repair. First what happens, there is a rust build up around the ABS sensor, it throws the air gap off on the sensor/reluctor wheel setup and it reads at a different speed, making the ABS think its locking up and activates the ABS. Also what can happen, once you have a little play in the wheel bearing, this can enlarge the air gap, making the problem worse.

Repair options

1. Remove the wheel speed sensor from both front hubs, clean the surface where the sensor sits of rust and the sensor of rust. However if your hub has some wear, the problem may return a little faster, since the air gap is already out some from the play, when the rust starts again.

2. Replace the hub/sensor assembly.

The front wheel speed sensor have too much rust and crap on them. Clean them and where they mount and that should clear up the problem. What happens is they are unable to sense wheel speed properly and drop out too soon causing the abs module to think the wheels are skidding.

:lol: Man beat me to it.

Thanks everyone.

I'll take a look at it Saturday.

I made an attempt to get to the wheel sensors last night. I say I tried because the bolts holding on the shield that covers them were stuck. I tried using a cheater bar but was afraid of striping the nut head off. I'll soak them for a few days and then hopefully they'll come out.
I did notice on one of the leads coming from the sensor that the wire was exposed as the insulation was rubbed off from coming in contact with the dust shield. I wrapped some electrical tape around the exposed area for now.
How can I tell if the wheel bearings are bad?
Can I buy just the bearings or do I have to buy the whole hub assembly?
How hard are they to change?

Again, thanks for the help.

2 or 4wd?

it's a 4wd

With the front tires off the ground, grab the top and bottom of the wheel and try to vertically rock the wheel in and out. If there is any freeplay, they need replaced. It is an assembly on 4wd, and all gets replaced. If you take the caliper and rotor off, you will see three bolts that hold the hub assy into the spindle. You access them through a hole in the bolt circle. You have to take the big nut off the axle, then the hub will come out.

the wheel bearings don't seem to have any play in them.

I tried to get to the wheel sensors for the abs but there is a dust shield that needs to come off first and the two bolts for it (that also seem to hold on the hub assy) are stuck. I'm soaking them in PB blast. I need to get an impact and socket to get them off I guess. That will give me a good excuse to go buy an impact wrench (off to sears I go today). Do I need to get the 15mm 6pnt socket or 12 pnt? Which will work better in this case?

Always use a 6 pt unless you have to use a 12 pt. 6 pt grabs way more of the bolt head than the 12 pt, which just grabs corners. I have never seen any impact sockets that were 12 pt.

My '99 Suburban is having the same problem, I think. Does anyone have a picture or diagram of the sensors?

thanks. Brian.

Can someone give me a primer on the antilock sensors, either cleaning or replacement?

Thanks for the help.

Brian.