Hi, my new to me 1990 4runner just started leaking brake fluid from one of the 2 brake lines
that run along the right side of the frame to the rear wheels. The line that is
leaking is the one that runs from(to) the arrow on the LSPV (see picture).










Now i dont know which line that is(i think it connects to the PS actuator?) and
if im going to have problems bleeding it since the Haynes manual says not to
touch the LSPV. I cant find any info on how to bleed the bypass line or how that actually
works. Is this a fairly straight forward job ? I just want to know if this
is something i can do on my own or if i should get a shop to do it. Iv bled brakes
before, but i want to be sure i know what im doing before i start taking
stuff apart.

Thanks in advance, Martin

 

The first thing I would do is to make sure that is what is leaking! It looks like there is some stuff on the frame rail also. You could have somebody pump your brakes while you are under there to see where it is leaking. As far as bleeding, I think that you would just bleed it like normal at the wheel cylinders. But Im not positive about that. On my truck I removed that lspv all together and did a straight line from the master cylinder to the rear. But that was the option I chose when I did the Leaf spring conversion on the rear.

 

Thats not my picture lol i stole if from another thread. Ok so i should be fine
bleeding it like normal? It is for sure leaking just behind the gas tank.

 

I would think that bleeding it normal would work just fine as long as you are thorough. Good luck.

 

Hey Im just following up on this in case someone has a similar question. The brake line I replaced was the return line for the front breaks. I had to remove the gas tank and replace the fuel line which broke in the process as well. I bled the breaks normally, starting from the furthest wheel and bleeding at the LSPV last, as per the manual.

 

In case you didn't know, there is an access panel that is under the rear passenger side seat for the gas tank fuel pickup. The 1st gen 4Runners have them as well as our 2nd gens. Just pick up the bottom section of the rear seat, peel back the carpet and you can see the panel held on with screws. I've used it on two occasions to replace the fuel pump and fuel line in that area with rubber FI hose on my 88. Just FYI...

Like Dras16 stated, I removed the LSPV in my 88 when one of the lines was rotted and leaking. It was a piece of rusted mess. I then plugged the return line fitting by the right front tire with JB Weld and added a manual proportioning valve from Summit Racing. I put the manual valve by the master cylinder under the hood. It worked out great.

 

yea I'm glad to see other people had to replace that rear brake line as well that was a pain and i was feeling a little laze and my gas tank bolts look like there were gonna all brake off so i manage to get it on with the gas tank still in the truck!