cold weather / brakes

[HURRICANES]

Just curious if you guys have run into the same issue I have had the last couple of days. I have a 99 Limited that is normally parked in our garage, but with the new purchase of the 05 SE the 99 is now going to be out in the weather. It has been pretty cold here in NC and the temps have been down in the single digits at times.. I have gone out the last two mornings started the 4runner and started to back out..both times when I have gone to put my foot on the brake at the end of the driveway the brake pedal has been hard as a rock and wouldn't budge so I have had to use the emergency brake! After sitting for a few minutes and working the brake peadal it starts to function normally. Is this normal with the cold weather or do I need to have it checked out? Once it warms up its completely fine...

 

[nevada]

Just curious if you guys have run into the same issue I have had the last couple of days. I have a 99 Limited that is normally parked in our garage, but with the new purchase of the 05 SE the 99 is now going to be out in the weather. It has been pretty cold here in NC and the temps have been down in the single digits at times.. I have gone out the last two mornings started the 4runner and started to back out..both times when I have gone to put my foot on the brake at the end of the driveway the brake pedal has been hard as a rock and wouldn't budge so I have had to use the emergency brake! After sitting for a few minutes and working the brake peadal it starts to function normally. Is this normal with the cold weather or do I need to have it checked out? Once it warms up its completely fine...

does that have the vacuum booster, or is it the all in one electronic unit?

if vacuum, take a look at the check valve. its probably bad.
when cold, the seal shrinks a bit and leaks. it reseals once it warms up some.

if electronic....I got nothing...

 

[LittleCaesar]

you need to replace the brake booster check valve.

Part# 44730-60060 at the dealership. You may want to replace the grommet as well #90480-24015.

 

[shootmymime]

Simple, i researched this to Mt. Everest and back.

Its a check valve that is getting stuck on the vaccum line that attached to the brake booster.

If you know how any of that works. great, if u want more detail, just ask.

but anyways this check valve is getting stuck closed and not providing you the normal power brakes you are used to feel.

after a few second the suction on the engine pulls open the valve and suction on the break booster start working again.

For a fix, you take the 10mm nut off the bracket that holds the hose on the break booster. and replace the check valve inside the line.

 

[shootmymime]

does that have the vacuum booster, or is it the all in one electronic unit?

if vacuum, take a look at the check valve. its probably bad.
when cold, the seal shrinks a bit and leaks. it reseals once it warms up some.

if electronic....I got nothing...

just to enlighten you further, electric boosters started in the 4th gens. i think its an over engineered design.

 

[Bt08231]

my 98 and 99 both did this exact same thing this week....

 

[TXLUGNUT]

interesting...same but slightly different problem...my brakes bleed fluid out of the calipers (out of the pistons even with a new seal kit) when it gets below, oh say, 15 degrees...I always figured I just needed a brake flush because "water" in the system was freezing and expanding the fluid out...

I'll have to check this out but here in Wisconsin it hasn't been above freezing for weeks on end now so it'll have to wait and I'll just keep adding fluid when the light comes on...:der:

 

[HURRICANES]

Simple, i researched this to Mt. Everest and back.

Its a check valve that is getting stuck on the vaccum line that attached to the brake booster.

If you know how any of that works. great, if u want more detail, just ask.

but anyways this check valve is getting stuck closed and not providing you the normal power brakes you are used to feel.

after a few second the suction on the engine pulls open the valve and suction on the break booster start working again.

For a fix, you take the 10mm nut off the bracket that holds the hose on the break booster. and replace the check valve inside the line.

I would like to replace it myself, but I have no idea what / where to look? Does anyone know of a writeup (pics preferred) ?

 

[HURRICANES]

you need to replace the brake booster check valve.

Part# 44730-60060 at the dealership. You may want to replace the grommet as well #90480-24015.

Thanks for the part numbers! I will check them out.

 

[shootmymime]

I would like to replace it myself, but I have no idea what / where to look? Does anyone know of a writeup (pics preferred) ?

the brak booster is the big 12" round black disc that is attached to the firewall under the hood in front of the driver.

attached to this brake booster is a master cylinder (MC), its the system creates pressure and moves fluid from the MC to the brakes to make you stop.
well look on the brake booster there will be a black hose about 1/2 going from it to the motor. that is the hose you need to pull off the brake booster. This hose is in the second picture. pull the hose off and the check valve is attached to the nipple assembly that is the brass looking part on the brake booster. remove that for you check valve.

 

[HURRICANES]

thanks for the pics... here is a pic of the check valve that I found. From the looks of it I would assume the check valve screws into the booster?

Toyota VALVE ASSY, VACUUM CHECK (FOR BRAKE) Part Number 44730-60060

 

[yosh2000]

thanks for the posts guys, had the same thing happen to me about a month ago on a new to me 99 limited...freaked me out! now i know what I need to do to fix.

 

[shootmymime]

thanks for the pics... here is a pic of the check valve that I found. From the looks of it I would assume the check valve screws into the booster?

Toyota VALVE ASSY, VACUUM CHECK (FOR BRAKE) Part Number 44730-60060

yup thats it, but not is does not screw on, so dont bother twisting it thinking it will unscrew, they are just ribs the help hold it it, to keep it from sliding out. i took mine out once and it took some strength and wiggling around to get it to come out.

 

[nevada]

yup thats it, but not is does not screw on, so dont bother twisting it thinking it will unscrew, they are just ribs the help hold it it, to keep it from sliding out. i took mine out once and it took some strength and wiggling around to get it to come out.

yeh, those barbs work good. they can be pretty difficult to remove.

I usually slide a screw driver behind and gently pry it out.

 

[LittleCaesar]

thanks for the pics... here is a pic of the check valve that I found. From the looks of it I would assume the check valve screws into the booster?

Toyota VALVE ASSY, VACUUM CHECK (FOR BRAKE) Part Number 44730-60060

Nope, it works just like a cork for a wine bottle. The valve is ribbed so that it is not blown out by the vacuum.

I included the grommet # since I have seen grommets tear (not on this 4runner though) when removing the old check valve.

15 minutes to fix, then be on your way. A set of good needle nose pliers are good to have handy.

 

[nevada]

Nope, it works just like a cork for a wine bottle. The valve is ribbed so that it is not blown out by the vacuum.

I included the grommet # since I have seen grommets tear (not on this 4runner though) when removing the old check valve.

15 minutes to fix, then be on your way. A set of good needle nose pliers are good to have handy.

 

[LittleCaesar]

Poor choice of wording by me for sure.

I had a new one crack on me (plastic Delphi crap) once when replacing a check valve in my uncles 305 Chevy but did not notice the crack until after I went to step on the brake and blew it out the booster still attached to the vacuum hose. Not ribbed. I guess Chevy did not care to seal up the vacuum in the booster.

I have heard check valves can be cleaned out with compressed air but for $30, why bother.

 

[Sierra946]

Just picked up a 99' limited 4 weeks ago. It has gotten down to -22 this winter here. First time the brakes did this freaked me out a little. $62 and a check valve & grommet later....problem solved!!

 

[shootmymime]

i took mine out today, sprayed WD40 and sucked it through the valve, i will check in the morning if it worked or not, trying to get the water our to help keep it from freezing.

its just a cheep temp fix, im broke and trying things b4 spending more money.

 

[Canuckrz]

Mine has done this a couple times. Are there any other problems a bad check valve can cause or just the problem on cold startup?