bleeding brakes on a car with abs

[markovr]

Ive bled the brakes on heaps of cars, done the master cylinder upgrade on cars with conventional non abs brakes without incident but havent tried doing it to a abs car.
Im thinking about doing a master vx upgrade on a vs with abs...any thing to be aware of when bleeding it?
Is there any special tools needed?

[petergl67]

Not really just bleed longest point to shortest. Easy as crack the bleeder on longest and let drip for a bit then continue until u get to the shortest point

[VrWagz1]

I cant say for sure mark, but i've done 2 vr ABS v8's(mine and a mates). I have had no issues with the ABS module, but i never let the resovoir run dry while bleeding the brakes (just as u usually do on any other car, the abs dosnt change the way you bleed the brakes), and also i make sure the lines are bent up as soon as they are removed so the fluid dosnt run out(not that much comes out anywayz, just a precaution to stop air locks)

From what im aware if you get an air lock in the abs module, your kinda stuffed and have to get tech1/2 on it to pules the abs to get it out. I do remeber a thread on here where i read that someone had this issue and they just either, 1>pulled out a wheel sensor or 2>strapped a nut or somthing metal over the removed sensor, to trick the abs to thinking a wheel is locked and causes it to pulse. The car was on jack stands and put in drive for this, which sounds dodgy but could get you out of a jam.
Now i dont know if you have to have pressure on the pedal, or lines cracked while the abs is pulsing, or maybe the pulsing just pushs back the air lock, or if this even works at all! But just passing on what i read It does sound feasible though.

[Brett_jjj]

If you bleed the brakes, and still find that they are a bit spongey, try locking up the brakes a few times on grass or gravel, which will activate the ABS modulator, letting any trapped air through, so it can be bled out, then rebleed them again. Dont let the master cylinder get below 3/4 from the full mark whilst doing the bleeding process, as it can easily suck in more air once the brake fluid gets a bit low.

[hako]

As long as you bench bleed the master cylinder before you instal it you should be right.

[GTP 85]

Ive bled many commo brake systems with ABS... VT setups on VS etc. I just do it as normal, never had any problems.

[Munz]

If you bleed the brakes, and still find that they are a bit spongey, try locking up the brakes a few times on grass or gravel, which will activate the ABS modulator, letting any trapped air through, so it can be bled out, then rebleed them again. Dont let the master cylinder get below 3/4 from the full mark whilst doing the bleeding process, as it can easily suck in more air once the brake fluid gets a bit low.

Locking the brakes won't be necessary, just an easy drive around the block - pumping the brake pedal - this will push the air thru the lines and then rebleed the system

[Brett_jjj]

Locking the brakes won't be necessary, just an easy drive around the block - pumping the brake pedal - this will push the air thru the lines and then rebleed the system

If theres any air trapped in the ABS modulator, just driving the car around the block wont activate the ABS to let the trapped air out from behind the actuators in the ABS module. Most quality scantools have an ABS brake bleed option which activates the ABS, this is so any trapped air in the ABS modulator can be let through to the calipers where it can be bled out. I use a Tech 1 scantool for this. I guess most aftermarket scantools would also have the same brake bleed option available. Locking the brakes is just a "backyard mechanics" way of activating the ABS. Ive bled a lot of brakes with ABS, and I hardly ever have a problem with air trapped in brake systems. But on the odd occasion, Ive ran into problems where Ive needed to use the scantool to get the air out of the system, and get the brake pedal firm where its supposed to be.. You would be suprised how much air can end up trapped in the ABS modulator.

[RX25SE]

Locking the brakes won't be necessary, just an easy drive around the block - pumping the brake pedal - this will push the air thru the lines and then rebleed the system

So where does the air go when you do this?

[hako]

So where does the air go when you do this?

It goes towards the caliper and then it returns from the caliper...unless the air is released from the system it will still be there.

[RX25SE]

It goes towards the caliper and then it returns from the caliper...unless the air is released from the system it will still be there.

Haha...
I've probably bled as many brakes as you Hako!

I was more curious about the logic behind the comment.

[hako]

Haha...
I've probably bled as many brakes as you Hako!

I was more curious about the logic behind the comment.

The real problem with pumping the brakes whilst air is in the lines is that the brake fluid becomes aerated with millions of microscopic air bubbles getting trapped in the fluid - only real fix then is a complete flush - this is also a reason why you don't re-use the brake fluid pumped out when bleeding.
Completely off topic, but I bought a '38 Chev Master back quite a few years...brakes were a bit spongy and pedal would not return so decided to bleed them and found the seller (dodgy car yard on Parramatta Rd) had used engine oil instead of brake fluid - apparently to swell the brake rubbers and stop leaks. There was no easy fix for that and it ended up at Sydney Showgrounds as a stock car where brakes were optional....it was a real shame to see all those solid 1930-40 Ford,Chevs and Chryslers etc being smashed to scrap every weekend at the stock car derbys....good fun but.

[RX25SE]

1930-40 Ford,Chevs and Chryslers etc being smashed to scrap

NOOOO.......





I've seen dodgy stuff before, but never engine oil in place of brake fluid!

Behaviour like that is what gives mechanics a bad name.

[jamdwan]

I had exactly the same problem. Squishy Pedal all of a sudden. Got brakes bled, no different. Did calliper seals on all corners, same squishy pedal feeling. Next was master cylinder - you guessed it, same squishy pedal. Was at a loss as next up was the option of braided brake lines. No thanks as they are over $500 installed in New Zealand!!!!

Looked at this thread Saturday lunchtime and saw what Brett_jjj had said in a reply: "If you bleed the brakes, and still find that they are a bit spongey, try locking up the brakes a few times on grass or gravel, which will activate the ABS modulator, letting any trapped air through, so it can be bled out"

I did this on the road straight after I read it, slammed brakes on at about 50kph. Pedal straight down no ABS activation. Tried again ABS kicked straight in, but pedal felt better. Did it a 3rd time and hey presto!!! ABS on straight away and pedal is now ROCK SOLID!!!!

Looks like is was inside the ABS module as you said. Been driving today and pedal is fantastic!!! No need to re-bleed the system.

So thank you so much guys for all your input. I may have spent around $600 doing everything but you saved me another $500 so much appreciated.

You guys ROCK!!!!