[PFC Hanson, Gregory]

Okay I feel really stupid for asking this since I am in the army and am currently deployed to Iraq and am a mechanic, but I am home on some R&R time and I have yet to work on an antilock brake system, so my question is, My wife recently had the master cylinder replaced, now I noticed when I had to step onto the brakes hard the tires had locked up, it was mentioned to me that the master cylinder might had been installed wrong, I need some guidance on what I can do to try to troubleshoot this problem to get this problem corrected, I would greatly appreciate any help that anybody could assist me with.

PFC Hanson, Gregory

[pepi]

can not answer this but can offer a thinking plan, first did a real mechanic replace the part or shade tree, if the latter I would contact a dealer and verify the part. Do you feel any anti lock happening like the peddle shuddering/pulsing. If that is happening then I would guess the system is working. Then the question would be are tires in good shape, not balding, cause the lack of friction will make anti lock skid the tires. No pulsing I would be looking for the unit that does this, like a solenoid close to the MC that maybe was left unplugged when the MC was changed, that was the last area worked on , or was the original problem you had repaired no anti lock if that is so then as you most likely know was not the problem. If the whole system all 4 sides are not working you are looking for a common part failure the pulsing unit itself or power to it...Sorry I could not offer more information but maybe have given you some ideas to confirm or question. enjoy your R&R best days in the military.

[PFC Hanson, Gregory]

I would just like to thank you for your guidance and your help, I greatly appreciate it. and you have a good one yourself.


PFC Hanson, Gregory

[joe_padavano]

Some cars require an electronic test tool to be connected to the ABS controller while bleeding the brakes. If this was not done, that may be the problem.

[Vortech 4.3]

PFC Hanson, Gregory

thank you for your service to our country :solute: . and welcome to the forum.

check to see if any connecters are off on the abs unit. and check any fuses.
are the rear brakes the ones locking up ?

[tbill]

what is your definition of 'locked up'? i ask this, as an antilock system allows 12% of actual brake lock up [give or take]. normally, when bleeding an antilock brake system for the replacement of a m/c, caliper or wheel cylinder, it goes just like a non abs system, the only time you need specialized equiptment is if an abs component is replaced that actually has fluid going thru it, in that case you need a scanner to open/close the valves inside the brake pressure modulator valve so all the air can be removed from the abs unit.

hope this helps some,

~tbill

[ernkazern]

Does the ABS warning light work? If so is it on? The ABS doesn't activate if the ABS light is on. ABS normally shuts off below a set speed, something like 8 or 10 mph as I recall. So if the brakes locked up at a low speed that could be normal.
What kind of vehicle do you have? 2 wheel or 4 wheel ABS? All ABS systems aren't the same.