Brake loss at high speeds
 

Ok so yesterday I was driving back home and as I'm going about 65mph+ I go to slow down and my brakes feel spongy real soft. That morning I didn't have any problems with my brakes. As I'm driving through town this morning I have nice firm brakes about 30mins later when I enter the freeway and I go up to 75mph+ I had to stop quickly when a car cut me off and to my surprise yet again no brakes, as the pedal traveled from about an inch from the floor I could feel the front ones engage and not the rear with loss of pressure. I got out when I stopped and check my fluid level and it's within the specified range between min and max. Can someone help me out on this? Thanks for all your helpful inputs.

it sounds like a busted brake line

Did you ever find any brake fluid under your car?

Have your changed your brake fluid?

Or do you have some crappy brake pads those are bound to screw you over

more information please :)

No didn't see any brake fluid under my car. Haven't done anything with the brake fluid except check the level of it maybe two or three times since I purchase the car. I changed out my front brake pads at the begining of this year I believe and haven't got to the rear ones yet. I purchased them from a OReilly's can't remember what the brand was exactly, but can get that once I get home this evening.

Something similar happened to me in an old chevy I had... was doin about 75-80 down the highway and when I went to exit, I came up on a 25 mph, u-turn off ramp... I applied the brakes and foot went completely to the floor... I repeated the process a few times and finally built enough pressure to slow for the turn (basically pumped and bled the brakes)... the next morning, I had brake fluid flooding the well of my right front wheel. :\.. busted brake line... The trip home (about 105 miles) was driven at no more than 45 mph, with emergency flashers all the way... had to use my gears to slow and stop the car in the city limits... was not very fun. :rant2:

If you don't have any cracks in the brake line, I'd have to wonder about your master cylinder.. perhaps it's not pushing the fluid like it should..

use this website and try to see what the exact part is if you can, itll make it much easier for everyone to help you diagnose the problem
http://toyotapartszone.com

hope it helps!!

Ok thanks Krem and 2jzmaestro for all the input I'll check to see if I have a bad brake line some where n go from there I'll keep you guys updated on the search.

How about brake fluid cavitation? It appears that this happens when the car is at higher speeds and when more is required of the brakes, right? The cheapest fix/diagnosis I can think of is to bleed the system with some good quality brake fluid and see if this still happens. Otherwise I think you're looking at a failed brake master cylinder or brake booster.

Ok I'll look into that thanks

The brake pads that I put on in the front are Raybestos; I'm going to put some on the the back and check my lines for holes, and my caliapers to see if they need to be replaced.

Also, you might want to check out your bleeder valves, I just changed a caliper and break pads for the rear, it freakin sucked and finally when I got done, my breaks would go right to the floor occasionally, turned out i didn't close the valves all the way LOL, sorreh for my stupidity.

So upon inspection of my system I notice that I do need to do a complete brake line flush due to the brake fluid looking like a dark brownish color in compared to a clear water color when it's fresh. I have also found a cracked line in my left rear side exposing the braided lines. So I'm just going to order some new Techna Fit performance brake lines all around. I also noticed on changing out my pads that they had some rust on the inside of it where it touches the rotor. This will be the last time I will be able to get my rotors resurfaced so next I'm going with the performance rotors. Eventually I'll be able to save up for a front and rear big brake kits; it's crazy how they cost as much as a high end turbo.

I believe after changing your brake lines and your brake fluid, your cars braking system is gonna feel much better. I hope this helps. The rust on the inside of the rotors (not the surface that touches the pad) is normal. As long as the surface that touches the pad is in good condition everything should be gravy.


Hope it heps :drool:

Thanks, I know you can't see it but the pads in the posting have rust spread lightly across the pad on the side that touches the rotor. That's why I changed them out to some new ones. I ordered my new brake lines still waiting for them to get here. Next time I'm going to upgrade my rotors. By the way does any one know a good website where I can purchase performance calipers? I just want the calipers and not the whole kit. Thanks.

A light surface rust is common in humid climate due to the soft, cast steel from which rotors are made. Especially in humid weather. It wipes off pretty much immediately and is of no concern. In addition to the surface rust some pads have iron and other materials in them which contribute to brown and reddish dust on the brake components. You're likely to see what you describe on any rotor... I don't think you've got anything to worry about there.

Definitely take care of the broken line and you might want to consider upgrading your brake fluid while you're at it. DOT 4 is far superior to the DOT 3 which came in our cars. Air in your system from the broken line is really the most likely culprit for all of the issues you're having with the brake system; changing the fluid is unavoidable since you'll be removing hoses, but it's advisable regardless. As for the rotors and pads, I'd clean them up with some sandpaper and see how everything feels with the fresh fluid and leak taken care of... if that takes care of it then you've got just that much more money to put into other upgrades.

Also, if the calipers didn't just slide off easily then the guides may be pitted or the grease may have emulsified. Clean the old grease off the guides and out of the caliper's holes for them and inspect them for pitting. If they're heavily pitted you'll need to replace them, otherwise just buff them with some 600 or higher grit sandpaper and regrease them liberally with the appropriate type of grease. You really should do this any time you take the caliper off (inspect and regrease) it's easy and cheap insurance.

2 months ago i had to replace ALL front pads calipers and rotors, and after that i lost all break power...
Replaced the "Master Break Cylinder" for 75 dollers,never had a problem again...

if you pump your breaks do you get anything???
do they build up over time??
small o rings in the master break cylinder could go overtime causing it too loose pressure thus having no peddle...
chek it out...

Update, now I have my brakes finished I'm going to go get a brake system flush and install my new performance lines. Upon doing some work over in the engine bay I noticed that my brake booster lines were cracked and had heat damage. So I had replaced the hoses and factory clamps with better ones. It seems like I'm not getting any pressure loss anymore, but still going to continue with the flush and line upgrades just to be on the safe side.