G'day, Im having some brake issues with my '86 4Runner. Im having to give the brakes a few little pumps before I get any amount of pressure on the pedal. The previous owner replaced the brake lines to both rear wheels and I have had the lines bled. My mechanic's idea is that im having problems with either the master cylinder or the splitter valve at the back and recommended me to contact Toyota to see if one or the other has historically been problematic. I havent gotten ahold of Toyota yet but wonder if anyone has any insight on this?

 

I don't know much about the splitter valve, but check if the fluid is disappearing. If the fluid is there, and it's not leaking, then you probably have air in the lines. Air will compress, while liquids do not. When you press on the brake pedal and you have air in the line, you end up compressing the air instead of pushing fluid and squeezing the brake. Bleed the brakes! It's a good skill to learn, or just get someone to do it for you. Brake fluid is cheap to, so it won't hurt to try.

Hope this info helps!

 

Look at first your rear shoe clearance and see if it is adjusted properly. The way to do this is jack up the rear, take off a tire, and spin the rear drum. If it drags, that good, if not, turn take off the drum and you should see a star wheel in the middle of the assembly, turn that with a flat head screw driver one or two clicks, put the drum back on and turn it. Oh while you have the drum off, look at your wheel cylinders and their sides. With a flathead, sort of lift the rubber boot on the wheel cylinders (don't need to lift it off) and see if there is brake fluid oozing out, if there is, you need new wheel cylinders, and that might be your problem.

The star wheel is located just behind that brown circular hub you see in the picture in the left hand corner. It will turn only one way (usually downward) to expand the shoes.

here's a better picture of what I am talking about, see that star thing in the left hand corner with like a tab on it?


This might give a bit more information and pictures on wheel cylinder replacment
(PS...if anyone needs info on rear seal replacment, article from 4x4wire forum gives great info.

Keep doing this until that drum drags (you'll know when it is adjusted when you feel the drum drag against the shoes as you turn the drum, don't have it drag too much), then I would also bleed the brake, and your "splitter valve" actually called a proportioning valve, bleed that first before starting the normal process (had two teachers at school, one works at Chevy dealer and other at Toyota, tell me both that it proper to bleed the proprtioning valve first, then others beginning with farthest wheel). If all else fails, look at your proportioning valve adjustment, that can be tricky to adjust and I would take it somewhere that doesn't call the proportioning valve a "splitter valve"...