[happysmp]

Need a bit of help
Picked up my 1996 sr5 last January and it had very weak brakes. Sometimes they wouldn't even engage when first starting the truck on a cold winter day. Found that the calipers were shot. I swapped these out for the 231mm tundra brake set up and it was great.

Yesterday had an extremely scary moment.
Started the truck, put it in drive and pressed on the brake when approaching the road and nothing! Absolutely no response... I was headed forward with cars coming ins it directions. I managed to stay clear but now I'm trying to figure out what went wrong.

Forums bring up disabling abs but I didn't feel the typical abs pulse in the pedal. It was simply unresponsive. Other search results show the brake booster, vacuum valve and grommet, master cylinder, and bleeding the brakes.

I don't think it's about bleeding the brakes as I just got a full brake job done last year and it was fine in the fall.

It has to do with the cold winter.... Help

[nevada]

Originally Posted by happysmp

Need a bit of help
Picked up my 1996 sr5 last January and it had very weak brakes. Sometimes they wouldn't even engage when first starting the truck on a cold winter day. Found that the calipers were shot. I swapped these out for the 231mm tundra brake set up and it was great.

Yesterday had an extremely scary moment.
Started the truck, put it in drive and pressed on the brake when approaching the road and nothing! Absolutely no response... I was headed forward with cars coming ins it directions. I managed to stay clear but now I'm trying to figure out what went wrong.

Forums bring up disabling abs but I didn't feel the typical abs pulse in the pedal. It was simply unresponsive. Other search results show the brake booster, vacuum valve and grommet, master cylinder, and bleeding the brakes.

I don't think it's about bleeding the brakes as I just got a full brake job done last year and it was fine in the fall.

It has to do with the cold winter.... Help

start there.

[Asaspades93]

I've read that part of the brake booster (i think) can freeze which more or less disables the brakes until it warms up a bit. I have a similar problem and on cold days I'll pump the brakes a few times before putting it in gear, the problem goes away within 10 seconds. hope you problem is a simple fix

[wjkrostek]

I haven't had that happen to me except with E brakes cable freezing up in the old days. It where me I would think Ice . So I would get a heat source like your wife's hair drier and start at the master and carefully thaw it out. When you find the iced spot it will start working again and you will know. Please let us know what you find out.

[happysmp]

Thanks for all the responses
Luckily it does come back after about 10 seconds. Can something really warm up that quickly? I'll try the grommet and vacuum valve as it seemed to be cheap and straight forward.

Pumping the brakes before throwing it into drive also sounds like a good idea. Will report back

[19963.4lsr5]

My wife had the same thing happen this morning. First time it happened and it was 1F outside. Till she came in to tell me and I walked out she had brakes.

But initially a hard pedal and no brakes.

I'm still thinking about the cause. We've had cold mornings before but not 1f but plenty of 10f mornings with no issues.

I was wondering if slush froze something or the high idle with it being that cold had low vacuum.

[Qyota]

It's the vacuum valve on the booster. Without a doubt. Some have had luck cleaning out and reinstalling. It's a $30 part...just replace it and move on with your life.

[happysmp]

Originally Posted by Qyota

It's the vacuum valve on the booster. Without a doubt. Some have had luck cleaning out and reinstalling. It's a $30 part...just replace it and move on with your life.

Ha ha
Roger roger

[Asaspades93]

i've been looking for the post on fb from @shootmymime , can't find it yet

[19963.4lsr5]

I agree the vacuum check valve is most likely cause.

[wc11]

Common issue with the extreme cold.

PN 44730-60060 valve
PN 90480-24015 grommet

[19963.4lsr5]

Removed mine this afternoon. Required a major amount of sucking to free up.

Sprayed brake cleaner through it both ways and some light penetrating oil and operates with the slightest amount of vacuum-me sucking on it. Also put a worm gear hose clamp on the hose. The spring clamp was it tight and hose moved freely on the nipple.

[19963.4lsr5]

Update. -3 this morning and wife said same problem. Guess I'm getting a new one.

[Brveagle]

It's such a "cheap" part to purchase, that it's not worth it to try and risk it. My opinion is to replace it with OEM.

[19963.4lsr5]

Since I am doing nothing but working and sleeping until Friday morning I swapped the one from the wrecked runner this afternoon. It will be -5 tomorrow morning. If no joy I'll call dealer and pick it up Friday after I wake up.

If new doesn't fix it it's brake booster time.