Should I remove my brake master cylinder??

[eurasiaoverland]

I've acquired a neglected 1996 Hilux Surf (JDM 4Runner) and I'm doing a very thorough overhaul on it.

I think the POs gave no attention to the hydraulic fluids. Both the clutch and brake fluid were black, and when I opened up the clutch master and slave cylinders they had black sludge in. I hate how cheap some people are, ruining good equipment with it.

Anyhow, the brake master cylinder also has black crap in it, and I really would like to take it out and clean it up. However, I have an ABS pump and I have no idea how to bleed that.

So my first question is if I can bleed the ABS system once everything is back together by just bleeding the master cylinder, then the rear and front systems? Or is there a special procedure to bleed the ABS pump??

Second question is regarding the brake master cylinder. It seems to have a second chamber offset from the main bore... what is this??

I bet my master cylinder is full of crap and I've heard that ABS pumps can rust out from dirty brake fluid, so I'd really like to clean the master cylinder out properly. However, if I will then need to take the truck to a dealer to bleed the ABS system, I will make-do with a good flushing of the master cylinder...

Thanks!

 

[nissanh]

Pull out the dirty fluid with a syringe and then replace with DOT 3 fluid. Then attach a rubber hose to the bleeding nipple and the other end to a big syringe. Open the bleeding nipple a bit and pull the dirty fluid out into the syringe. Continue until you see clear fluid in the syringe. Make sure to replace the lost fluid in the master cylinder time to time. Do this for all 4 wheels. Finally with a help of another person bleed the system as you normally do.

 

[eurasiaoverland]

Hi

Thanks for your reply, but I was asking specifically if there is a procedure to bleed the ABS pump. I'm fine with bleeding the master cylinder (which on my truck has no bleed nipple), and at each wheel.

The fluid has all been drained from the master cylinder reservoir, but there is black sludge in there which I want to get out. I doubt it will flush through as it is at the bottom of the three-way split reservoir sectors. Hence wanting to disassemble.

So, do I need a special tool / dealer visit to cycle the ABS pump, or will it bleed through with a conventional master cylinder / rear cylinder / caliper bleed procedure.

 

[nissanh]

Hi,
Never seen a toyota with a bleeding nipple fitted to the master cylinder.

Before you visit the dealer, try doing like I explained above (this is how I do for my 4runner with ABS). Make sure to pull the fluid from each wheel. After doing all that, check your brakes at slow speeds at home and slowly speed up and see how it handles.

If you see any problems then take it to the dealer.

 

[seank]

The easiest way to be bleed the ABS actuator is activate it after having performed a full flush to all four wheels with fresh fluid. It will take more brake fluid than normal because you will have bleed the whole system at least twice, but it will get the bad fluid out.

* bleed brake as [MENTION=85046]nissanh[/MENTION] described
* find a slick or better yet icy road and go up to 40 kph, then brake hard to active the ABS
* repeat four or five times
* bleed the entire system again as normal