No power brake boost at extremely cold temperature - Toyota Nation Forum : Toyota Car and Truck Forums

Mike Gerber · 12-07-2005, 03:56 PM

This morning I experienced something strange. The temperature was around 0 here this morning in the Chicago area when I started my 94 Camry 5SFE. The car started without a problem. I let the car idle for about 60 seconds before driving off. When I attempted to make my first stop after going about 50 feet, I had no power assist. The pedal was rock hard and I had very little stopping power. I went slowly around the block and on about the 3rd or 4th braking attempt the pedal finally dropped down a bit and the power assist returned. I'm sure there must be some moisture in the vacuum line to the booster assembly that had frozen solid. Has anybody ever experienced this? If so, what was the fix? Will the engine vacuum remove the moisture? Does the check valve need to be replaced? Any help here would be greatly appreciated.

Mike

Cyorke · 12-07-2005, 06:57 PM

Mike have you tried looking at the repair manual that is stickied. I am sure you ahve it already but maybe it would give you some ideas of what to check.
I cant say as I ahve ever had that problem and dont rememerb ever seeing that problem when I was working for Toyota. Of course it doesnt usually get taht cold down here and I try to keep my car in the garage at night so I dont have to scrape windows and worry about stuff like taht .

bronzemaxell · 12-07-2005, 07:10 PM

Quote:

Originally Posted by Mike Gerber

This morning I experienced something strange. The temperature was around 0 here this morning in the Chicago area when I started my 94 Camry 5SFE. The car started without a problem. I let the car idle for about 60 seconds before driving off. When I attempted to make my first stop after going about 50 feet, I had no power assist. The pedal was rock hard and I had very little stopping power. I went slowly around the block and on about the 3rd or 4th braking attempt the pedal finally dropped down a bit and the power assist returned. I'm sure there must be some moisture in the vacuum line to the booster assembly that had frozen solid. Has anybody ever experienced this? If so, what was the fix? Will the engine vacuum remove the moisture? Does the check valve need to be replaced? Any help here would be greatly appreciated.

Mike

i have similar problem on my 94 v6le, when ever temperature drop below freezing, like 32F or below, if the car has been parked for 4hour +, when i start the engine, and step on break, it has no brake, rock hard, what i've found out is, before i shift from P, i step on the brake padel for 5 to 10 seconds, and feel the brake drop to floor a bit, release foot on padel, then the brake has power assist, and it will brake fine until i park it for a while, and problem repeats. In summer, i have no problem, only in winter problem exist.

Gary_602Z · 12-07-2005, 07:24 PM

Mike, I think you might be right about moisture in the brake system. I would not think that the engine vacum would remove any moisture from it otherwise howwould it had formed? I do not really have any ideas how to get it out. Don't truckers use ether or something on their lines?

Man I think this is the first time I have ever seen you ask a question!

Gary

Cyorke · 12-07-2005, 11:01 PM

Quote:

Man I think this is the first time I have ever seen you ask a question!

I was thinking the exact same thing when I saw this thread.

GrantTPC · 12-08-2005, 12:05 AM

Strange... I was going to post about exactly the same thing about the cold weather.. but with my 92 Camry... But my problem is the brakes feel to-the-floor soft... like Bronzemaxell

Mike Gerber · 12-08-2005, 01:33 PM

Quote:

Originally Posted by Gary_602Z

Mike, I think you might be right about moisture in the brake system. I would not think that the engine vacum would remove any moisture from it otherwise howwould it had formed? I do not really have any ideas how to get it out. Don't truckers use ether or something on their lines?

Man I think this is the first time I have ever seen you ask a question!

Gary

Quote:

Originally Posted by Cyorke

I was thinking the exact same thing when I saw this thread.

Gary and Chris,

Everybody experiences something new now and then. That's part of the fun and reason for these forums. We all have a pool of experience and information to fall back on.

I talked to a friend who is a Mazda tech. He said Mazda had the same problem on some of their cars. He varified it is condensation in the vacuum line to the brake booster. He said it is usually in the check valve. We pulled the vacuum line off the brake booster and while I kept the engine reving a bit, he sparyed some carb cleaner in the line. Took about 30 seconds all together. He said that's what he would do if it was his car. That should eliminate the moisture. He said that if a Mazda is still under warranty he would replace the check valve (which incidently is in a rubber hose on Mazdas). If not, he says he just sprays carb cleaner through the line to disperse the moisture, or if he takes the hose with the check valve off the car, he uses brake cleaner. When dry, he just puts the hose back on. Learn something new very day. I hope this solves the problem. I wouldn't be too sad if the temperature never got that cold again this Winter for me to check, but I know we won't be that lucky.

Thanks guys.

Mike

Cyorke · 12-08-2005, 02:11 PM

so I am assuming that if you spray the cleaner into the line it is a long term temporary fix. IF taht makes sense. I guess the moisture is jsut from normal everyday use and the check valve is not able to keep this moisture from getting into the booster or is the moisture in the booster nad making its way into the line. I have never had anything like this happen on any car I have owned or any car I ahve ever repaired so jsut trying to figure out a little more I guess.

Mike Gerber · 12-08-2005, 03:48 PM

Chris,

I don't really know if it's a long term or temporary fix. The car ran fine once the booster starting working again yesterday. The brakes worked fine this morning but I think the temperature was around a balmy 10 degrees this morning; about 10 degrees warmer than yesterday morning.

I too think the moisture is just from everyday use. If brake fluid, being hydroscopic, can pick up moisture, I would assume the air in our vacuum lines can do the same form all the heating and cooling cycles it goes through. I don't really know for sure. I'm guessing the moisture was actually frozen in the check valve itself and that was keeping the booster from getting the necessary vacuum it needs to work effectively; but that's just an educated guess. I'll just have to wait and see the next time it get's real cold here. If it get's that cold again soon, I'll know to give the car a little more time to warm up and will try the brakes a few times when standing still. That feeling of having almost no brakes and not being able to stop is not one I want to experience again.

Mike

Gary_602Z · 12-08-2005, 04:43 PM

I have a buddy who is a mechanic that swears certain brands of carb clean contain a fair amount of water in them. Might be something to watch out for if you are using carb clean?

Good luck and let us know.

Gary

Mike Gerber · 12-09-2005, 10:26 AM

Thanks Gary. I'll keep a watch on it.

No problem this morning, but the temperature was a warm 17 degrees. I really didn't drive the car. I just moved it out of my driveway so I could shovel the 7 inches of snow we got yesterday afternoon and last night.

Mike