toyota break problem

[wyota]

so ive had a GM HD master cylinder and a toyota adapter for over a year now and decided to give it a try this weekend. After getting it installed and the system bled i really didn't notice much of a difference. I had read that I should have gained around 30% over stock(still ifs and drums). Well as my luck goes I think my breaks got worse, or at least they didn't get any better(i think i got hosed on the MS it was a CL deal). So for my piece of mind i put the Toyota MS back on. Now i cant get it back to oem stopping performance. So im going to start with the basics to make sure i haven lost my mind, and the symptoms. The pedal feels a bit soft on top but has good "grab" but as soon as i get to half pedal it feels overly hard and has little stopping power. Now if some one where to tell me this i would say that they have air in the system. i have bled this thing from front to back, back to front and still have had little change. also if i press the pedal while the truck is running and hold it and turn the truck off the pedal dose not drop, witch contradicts having air bubbles :confused: any idea's?

1. when bleeding breaks you start at the closest wheel to the MS? i read an article yesterday that your supposed to start farthest from the MS, witch is it for a Tacoma?
2. on a tacoma do you bleed the rear brakes from the wheels or the proportioning valve on the frame?
3. since i removed the MS but never drained it should i have bench bled it before reinstalling it?

[Chris]

Hey Todd, it does sound like air to me but I'll defer to others with greater expertise but will provide my 2¢

1. farthest
2. wheels
3. yes

[Geno]

I always bled the MC first, bench first, and then in truck ( so you dont push air down the line of corse) then start from farthest wheel, I have never bled the proportioning valve because I really move a lot of fluid through the rear brakes when I bled them. My pedal is hi and full two hands on the wheel pedal stomp it never goes below 1/2 (and my Taco does not have ABS) . GM MC are built with different size res. for different fluid movement to there brakes ( example 11 front disc dana 44 3/4ton and 14 bolt 13.250 rear drum which take a huge amount of fluid, factory in the same truck) where Toyota trucks have a closer fluid amout movement, hense the rear toyota proportioning valve to help with changes in load conditions in the truck. Valve open more, more fluid to rear = more rear brake pressure, so front tires dont lock up so easy. Maybe the chevy MC and the rear toyota valve were doing the old power control fight. just a guess on that .

[Brody]

1. when bleeding breaks you start at the closest wheel to the MS? i read an article yesterday that your supposed to start farthest from the MS, witch is it for a Tacoma?
2. on a tacoma do you bleed the rear brakes from the wheels or the proportioning valve on the frame?
3. since i removed the MS but never drained it should i have bench bled it before reinstalling it?

Gene is dead on, but I am going to add a bit.

You can bleed the proportioning valve, but this is usually only done if you have replaced it. And it can be done on the frame. Generally these get left alone.

It never hurts to bench bleed anything whether it is a new or re install. Just saves some hassle.

What I would do if I were you, would be to gravity bleed the whole system for a bit. Just grab a big bottle of brake fluid, open the hood, and crack all of the bleeder valves on all of the brakes, letting them drip. When you have a good constant drip going on all of them..and be watching your fluid all this time, start closing them off the exact way you would bleed them, farthest to closet. Top off the brake fluid and then try to bleed them normally.

[wyota]

Thanks every one!! I walked away and came back to it today and now they work fine!? I'm leaving to go wheeling for three days. I'll make sure to take a bunch of fluid with me in case it decides to go south on me. On a side note I ordered a manual rear proportioning valve from front range off road. when it gets here I'll try the GM MS again.