Brake Pressure Loss. Reason?
Thread Starter
|
Trailering
Joined: Mar 2004
Posts: 15
Likes: 0
Brake Pressure Loss. Reason?
Last fall I had to hit my 03 Expy brakes hard at 70 mph. After doing this, I slowly lose brake pressure and I have to pump my brakes a few times to build up pressure. Is this most likely my brake booster leaking or could it be my master cylinder? I have bled my brake lines and the master cylinder doesn't leak at all. What is the best way to figure out where the pressure leak is?
Thanks,
Mike
Thanks,
Mike
Temporarily Deactivated
Joined: Aug 2009
Posts: 969
Likes: 1
Is the brake fluid level dropping?
The level in the resevoir with go down normally as the brake pads wear though so you have to keep a close eye on it.
I have seen brake fluid leak into the brake booster through the back of the master cylinder and get sucked through the vacuum line where it is burned in the engine leaving no trace of a leak.
Otherwise, you should do a thorough inspection under the truck for leaks.
One distinct possibility is that you simply experienced brake fade during the panic stop. When I was racing it was required that brake fluid be replaced annually. If not, it aborbs water which can contribute to fade. One other important factor is pad thickness. When the brake pads get thin more heat is transfered to the calipers, where the brake fluid is. The combination of worn pads and old fluid could have definately resulted in the fade you experienced. If that is the case, bleeding the brakes was the correct course of action, a flush would be even better.
The level in the resevoir with go down normally as the brake pads wear though so you have to keep a close eye on it.
I have seen brake fluid leak into the brake booster through the back of the master cylinder and get sucked through the vacuum line where it is burned in the engine leaving no trace of a leak.
Otherwise, you should do a thorough inspection under the truck for leaks.
One distinct possibility is that you simply experienced brake fade during the panic stop. When I was racing it was required that brake fluid be replaced annually. If not, it aborbs water which can contribute to fade. One other important factor is pad thickness. When the brake pads get thin more heat is transfered to the calipers, where the brake fluid is. The combination of worn pads and old fluid could have definately resulted in the fade you experienced. If that is the case, bleeding the brakes was the correct course of action, a flush would be even better.
Thread
Thread Starter
Forum
Replies
Last Post
Hound Dog Lew
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
2
Jul 12, 2017 08:13 AM
Oldbluer
1967 - 1972 F-100 & Larger F-Series Trucks
29
Jun 15, 2017 05:35 PM
Amish65F100
1961 - 1966 F-100 & Larger F-Series Trucks
38
May 25, 2017 11:10 AM
Saligli
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
1
Nov 3, 2016 09:19 PM
rustywheel68
1967 - 1972 F-100 & Larger F-Series Trucks
10
Dec 4, 2015 08:14 AM
