Scatterbrain

Is this a Load Sensing Proportion valve? It's next to the rear tire on the passenger side. Not that I understand what that means at all...just wanna know what the actual part is before I "attempt" to fix it...
Quick history.... 87 4runner 22RE stock
About a month ago I bled all the lines, replaced front brakes and cleaned drums on back. Everything was tight and working well. Suddenly today I have no brake pressure at all. Looked around underneath and found the leake. The little black rubber ball...portion... of that part was slightly leaking from the connecting lines when I would squeeze it, but was actually squirting fluid out of the side....so I would assume it has a hole in it. Could some kind soul direct me to some walk through to replacing this?

**Side note** Couldn't ever get emergency brake light to go off even though brake would be disengaged. When I redid my brakes the light would finally go off, but it just started staying on again the other day. Now that I have no brake pressure, the light is off again. What could the culprit be?

All help greatly appreciated.

scope103

Check it out yourself:
http://personal.utulsa.edu/~nathan-b...12loadsens.pdf

tj884Rdlx

Yes that is the LSPV. Repair or replace the leaking part. Until you do, watch your fluid level. Low at the master cylinder will trigger a warning light.

Google "repair lspv Toyota" if the link already provided isn't enough info.

Remember that the way that thing works is based on how high your truck sits in rear, and if a lift was done a bracket on the axle should be extended. There's plenty to read here discussing this pretty common service item.

Also, order of bleeding all four wheels, the master, plus this part, is important. Do it right the first time by confirming the correct sequence. (Which i don't remember or I'd just describe it, sorry). Good luck

AKHeathen

master cylinder, then lspv, then rear wheels, then fronts. remember that the lspv feeds up to the passenger side front and back, so you may get air trapped there.

Scatterbrain

If it's just the rubber reservoir, can I just replace that? Not sure where I would even find one without buying the whole part...which is expensive. Sort of look like there's just a metal ring holding it on. Is that not a brake line running into it? The diagram looks as if its hooked inside of the entire part.

dropzone

iTrader: (6)

YES, the load sensor proportional valve has brake lines, it is part of your brake system. More than likely the fluid you see on the rubber boot is brake fluid.
you need to get the leak fixed. The rubber boot is not a reservoir. The brake fluid leaking is coming from the reservoir under the hood, leaking from a fitting or the valve itself.

there is a parts source thread sticky in newbie tech with tons of links of where to find parts

AKHeathen

the rubber boot you see is nothing but a dust cover, to keep junk from getting into the piston. it's much like your master cylinder, wheel cylinders and clutch cylinder. when it leaks fluid it needs to be replaced or rebuilt.

Scatterbrain

Ah I see. My confusion spawned from the fact that whenever I squeezed it, a pin size hole leak would arch fluid out like a little water balloon. So if I understand this correctly, that's just a cover that somehow filled with brake fluid from an actual leak inside? (Giving the appearance that's its a "filled reservoir"

DemonRunner

DemonRunner

Scatterbrain

Do you know if it still functions properly?

Scatterbrain

Any idea if I'd be able to take it to a shop as is and have em install it?

AKHeathen

well, i could be liable if i told you it's okay and you got into an accident for any reason. however, i would on my own vehicle, if it isn't emptying the reservoir along the way and the brakes still work, but that is me. if you do, do it at your own risk.

Scatterbrain

Haha I didn't mean driving the actual vehicle to the shop, I meant having them install the part the way it is, or if anything in addition would need to be done. I suppose I'll try myself, just not sure about what tools may be necessary for removing the lines and what not. I have minimal tools, but everything needed to change/bleed brakes. I was under the impression it took some special tools to make sure it has the right pressure settings, also wasn't sure how the brake lines were connected.

AKHeathen

metric brake line wrenches. i'm not sure how close the adjustment would be out of the box, but i'm sure there are threads on adjusting it.