I have a 1986 toyota 22re pickup sr5. I have recently replaced my brake booster and master cylinder, and flushed out my old brake fluid. I have added new fluid and bled the system and bled the lines in the order I thought was correct (MC, PR, DR, PF, DF, LSPV). However, there is still air in the system. So I went to the forums, and I've noticed there are a couple different bleed orders. So I have now tried every permutation and there is still air in my system. Any help would be greatly appreciated. Thank you!

 

Is the pedal actually "spongy" and not firm? That's the only sure sign of air in the system that I know. If so, try bleeding the LSPV first. It's been known to be an "air trap" before. Other possibilities:

1. Did you 'bench bleed" the MC? Most come with a kit to do this and it can be difficult to get the air out of the MC when installing a new one.
2. Re-check your line connections to the MC to make sure they are firm. Sometimes air can get drawn into a slightly loose connection. Also check the rest of the line connections on the truck for the same reason.
3. Check your flex lines. The rubber lines can get soft over time & expand a bit when you put pressure in them (from stepping on the brake pedal), flex outward & this results in reduced fluid pressure.
This can feel like air in the system. Your truck is a 1986; how old are those lines? Have a look at them for cracks, feel them for soft spots or hardness/brittleness. If you find any of this, replace them.
4. You didn't mention calipers or wheel cylinders; how old are they? Seals in these can also leak, either fluid out or air in, or both.

Point of all this being, it's always best to check the entire system you are working on. I can't tell you how many times on an old vehicle I've replaced a single component, thinking that was the only issue, then had to go back and address something else in the same system.