Got some questions on my 87 Toyota 4Runner!

[BSchorr]

Ok, I have some symptoms and various questions for you guys..

1. What is this white plastic screw with the spring behind it? I counted about 2.5 turns out from closed...



2. After my truck warms up good to normal operating temp, every time i hold down on the brakes, the idle drops for a quick second, and then comes back to normal idle... and it keeps doing it.. like when your at a red light... Well my thought is.. The brakes on this truck are power brakes.. so they work with vacuume.. right? So the only line coming from the brake booster is the line on the back firewall up top. It has a white thing spliced into the wire? think that could be the prob?

3. What is the coolant bypass/switch thing? what knob on the temper gauge bezel is it connected to? Is it to stop the flow of coolant to the heater core, so you can have cool air blowing through the vents?





4. My airhorn scares the crap out of people who are walking on the side walks!!! haha

 

[03vrod]

not sure on the vacuum thing with the plastic nut,If no one else answers I'll look it up.You probably have a vacuum leak at your brake booster may be bad.The lower right slide control the one that says heat or cool that's connected via a cable to your heater control valve on the firewall

 

[BSchorr]

not sure on the vacuum thing with the plastic nut,If no one else answers I'll look it up.You probably have a vacuum leak at your brake booster may be bad.The lower right slide control the one that says heat or cool that's connected via a cable to your heater control valve on the firewall

Makes sense with the temperature slide control...

So you tink the brake booster could be leaking other then the 1 hose coming out then?

Can you see what that white plastic knob is for? I do not have a repair manual.

 

[03vrod]

I haven't replaced one on a toyota but many other makes.If it only does it when the brakes are applied then i would think it was the booster.You could go by a shop and have them test it before you replace it.If it were the hose it would leak all the time not only when applied since the hose always has vacuum on it.You could crimp the hose and try it in your driveway don't drive it on the street disconnected the brakes will be very hard to press and you may have an accident.Is the truck a auto or manual transmission?

 

[BSchorr]

2.2RE Manual 1987 Toyota 4Runner

 

[turboSR5]

That white plastic knob is your auxillary idle up, it ties into your AC VSV and power steering vacuum lines. It has the screw top on it to adjust how much the system revs your idle when under load from P/S or A/C AFAIK.

The white thing in your brake booster line is just a coupling to tie in the 2 seperate hoses, at least i think that is what you are talking about, that's the only white thing I noticed in your picture.

 

[03vrod]

Thanks turbosr5 I was wondering how they accomplished that without an IAC.Bschorr does your truck only stumble when the brake is depressed.After you drive it leave it running and pull the emergency brake instead of holding the brake down.Is the problem there?

 

[fourwd1]

That "white thing" in the vacuum line (not wire) to the brake booster is a check valve, not a splice.

And check your idle RPM, if it is higher than spec, it can cause your brake idle problem.