Bleeding Brakes on RWAL

brakes
chevrolet
s-10

#1

I have heard about so many problems when bleeding antilock brakes. I am wanting to embark on installing a new master cylinder and rear wheel cylinders. But there ahead looms some nefarious issues to be encountered unless I have a Tech-1 scan tool to reset the antilock modulator if it is so needed. Is it possible to work around buying a scan tool for this small job? I have read online of those who have bled their brakes and would be bleeding their brakes(as they say)until hell freezes over. Surely there is a way devoid of a Rube Goldberg machination.


#2

There is no problem bleeding the brakes. The common problem with working on ABS brakes is pressing the caliper piston in with the bleeder valve closed. Doing so forces a great deal of fluid to flow back through the system which often causes the ABS controller to fail. If the bleeder is opened when the piston is pressed in there should be no problem. And to bleed the brakes just open the bleeder valve slightly and install a short piece of tightly fitting hose on the bleeder and keep it pointed upward while pumping the brake pedal until fluid streams from the hose. No help is required.


#3

Thanks, well that sounds logical and straight forward. I had been reading about the piston in the abs modulator trapping air and not been able to get it out unless the piston was recycled and that would require a tow to a shop unless you had a scanner to reset the abs functions. It did sound awful complicated for such a simple job.


#4

Instead of a Tech 1 scan tool, just drop $20 on a repair manual if you don’t have one. It should provide the recommended bleeding procedure (including a bench bleed of the master cylinder) and include any warnings about what not to do. You will likely find, as Rod Knox said, that unless you need to mess with the ABs module itself the procedures will look pretty conventional.


#5

Thanks, that 20 bucks is better than several hundred for a scan tool. I suppose I will soon find out the scoop on the deed.


#6

The factory service manuel for my 2002 s10 says that you must computer bleed the ABS unit using a tec2 scan tool every time the system is opened up. I don’t know if there is a special way around this, but I would look into it, or find a mechanic friend with a scantool to bleed it for you after do the work.

Also I don’t know what year your s10 is and also my mech has a solus and he has a bleed procedure he can select to do it.


#7

Yes that is what I have been hearing about the “touchy” abs system. I have a '95 with rear abs and I would just as soon not have abs at all for it complicates brake work for poor people.


#8

You don’t need scan tool to bleed the brakes on a 95 RWAL system. Here is the procedure and note it says nothing about using a scan tool.

The ignition switch must be in the Off position or false diagnostic trouble codes may be set to memory.

Install bleeding tool No. J-39177, or equivalent, on combination valve.
Check master cylinder reservoir fluid level and fill if necessary.
Relieve vacuum reserve by pumping brakes several times.
Fill master cylinder reservoirs with suitable DOT 3 brake fluid. Maintain fluid level during bleeding.
If master cylinder is suspected to have air in the bore, bleed it before any wheel cylinder or caliper as follows:
Disconnect forward brake pipe connection at master cylinder and allow brake fluid to flow from connector port.
Connect brake pipe but do not tighten.
Slowly apply brake pedal and allow air to bleed from loose fitting, then tighten fitting before releasing pedal.
Wait 15 seconds.
Repeat this sequence until all air is purged from master cylinder bore.
Repeat procedure for rear pipe.
Bleed each wheel in the following sequence:
Right rear.
Left rear.
Right front.
Left front.
Attach tool No. J-28434, or equivalent, to wheel cylinder/caliper bleeder valve. Immerse opposite end of hose into suitable container partially filled with brake fluid.
Slowly apply brake pedal one time and hold.
Loosen bleeder valve to purge air from wheel cylinder/caliper.
Tighten bleeder valve and slowly release pedal.
Wait 15 seconds.
Repeat sequence until all air is purged from wheel cylinder/caliper.
Torque bleeder valve to 62 inch lbs.
Perform preceding bleed steps at each wheel until system is bled.
Check brake pedal for sponginess and the brake warning lamp for indication of unbalanced pressure. Repeat bleeding procedure to correct either condition.


#9

I have a Haynes Manual for a 2002 Chrysler minivan and here is what it says about bleeding the brakes after replacing a brake line,caliper,wheel or master cylinder.
TOW TO DEALER TO HAVE BRAKES BLED!


#10

I have a Haynes manual for my '00 GM minivan that gives a perfectly conventional bleed procedure for everything except the ABS module itself.

Haynes manuals do have their uses, but anyone who’s actually owned one knows that they’re very incomplete. I have very frequently gotten the feeling that Heynes basic MO is to insert “take it to a dealer service department” whenever they’re just too lazy or not smart enough to actually provide the procedure.


#11

Thanks immensely for that detailed reply. Seems straightforward enough by just following the numbers. Very good.


#12

One added suggestion: I always suggest connecting a clear plastic hose to the bleeder before opening it, running the hose into a clear vial 1/2 full of brake fluid and suspended as near the bleeder as possible. That way the air burps out when you push the piston in and any backdraw pulls back brake fluid rather than air.


#13

Thanks point taken