Weird brake bleeding problem '99 Tacoma V6

Hi guys,

I've lurked for a long time but never really posted, but I spent the day in the shop working on a brake problem and thought you guys might be able to help me tie up a loose end..

I was driving the other day and my pedal started going spongey all the way to the floor. I assumed air in the lines. I hooked it up to a bleeder machine and when I first loosened the valve (passenger rear) some came out, but when I put the hose on, none came out. As I went around bleeding all the tires in order, the same thing happened.

So basically I pulled out all of the brake fluid that was left in the lines and they're dry, with no more being pumped in anywhere.

My first thought is the master cylinder because I don't see any reason it would be clogged. Is there any chance the ABS system would fail? The problem has to be before the lines.

Before I bled the brakes, I could at least brake a small amount if I pushed to the floor hard. Now I have no braking capability at all.

Thanks for any input. Cheers!

 

hmm a little confusion here... your info says you have a 2013 TRD... this is the 1st gen forum. Different and the same at the same time, if you know what I mean.

 

Woops, my apologies. I have a 99 V6 TRD.

 

ok, no problem.

how old is/was the fluid? the reason I ask is that if there is crap in the bottom of the resivoir stuff might have gotten into the master cylinder.

 

It is safe to say that it was old. Is there a good way to flush out the lines and cylinder?

 

if you have the time I would pull the resivoir off and then the master cylinder and take the MC apart and look at all the seals, pistons etc. If she looks good, bench bleed it and reinstall. There is a possibility that the rear seal on the master cylinder leaks and brake fluid is pulled into the vacuum booster, if so, and it hasnt been too long you might be able to get it out. If not, it is just a matter of time before the rubber diaphram goes away.

 

My 2004 was a pain to bleed. You need a good bleeder/vacuum tool to pull the fluid from the MS, thru the ABS unit and finally thru the bleeder.

Always keep the resivior topped off as you pull fluid thru the system lines.

It took me 1.5 quarts to get a quality bleed.

My brakes are amazing now.

 

unfortunatly there is no quick and easy way to clean it out... the crap that was in the fluid just might be binding the ABS pistons from performing their job. All you can do is try to flush the system with new bake fluid. Like I said above, bench bleed the MC and reinstall then take the right rear bleed screw out completly to make sure the hole is free of crap then either get a buddy and do the up down open close routine or use a brake vacuum bleeder that you can get at the auto parts store. Do the same for all other and dont forget the load sensing valve over the rear axle. When you have a good pedal, take her for a run and find an empty streach of road, get her to 30 ish mph and try to lock the brakes and see if the ABS cycles. If it does, do this few time then go back and re blead. Some manufactures build in a ABS bleed cycle into the OBDII system to accomplish this in the shop.

 

Okay, awesome. I'll start with examining the master cylinder and seeing what I can find. Will report back when I find out more.

 

In case you missed it in Glamisman's post, I'll repeat it. There is a proportioning valve above the rear axle that needs to be bled also.

 

Thanks for that. I noticed that and did bleed it, but I wasn't sure what it did.

 

It's a struggle to bleed one of these ABS systems w/o using Techstream to properly cycle the solenoids in the ABS.

@Glamisman is suggesting a workaround for that, but it still winds up being time consuming as @koditten experience shows.

I had the same issue with my '04 Highlander when the master failed.

 

Hey guys. Wanted to say thank you for all the help and troubleshooting.

I replaced the master cylinder today. I bench bled it beforehand and then did a regular brake flush. This fixed the issue.

When I inspected the old master cylinder, I noticed the problem. There is a primary and secondary valve. The secondary valve is the furthest from the brake booster it is mounted to, I believe. It was what pushed the brake fluid to the front brakes. When I pushed it in, the piston just wasn't making it all the way to the end.

When I brake pumped and bled, I could get small amounts to the rear, but still the same dry pump in the front. The failed piston in the master cylinder is what caused this. I was told to do a brake flush every two years and you'll never have to replace a master cylinder.

Either way, it's fixed. Appreciate the help.

 

sweet... fyi, brake fluid pulls moisture from the atmosphere and that is the reason for its periodic replacement. I suspect that the aluminum piston suffered from corrosion due to water in the brake fluid.

 

Definitely a safe bet. Now on to the intermittent ABS light. Definitely the sensor. Always something, right?

Thanks again guys.

 

Yeah, it def is always something. But if you keep up with it I can tell you it will last as long as you want it to. GL