Low brake pedal?

9 LIVES

9 LIVES

Demolition Expert
Joined
Oct 29, 2006
Messages
4,051
I've got a 1994 2500 I recently purchased off craigslist with brake issues.

The first stop of the day (coming out of my driveway) it will act like it has NO brakes and then all the sudden lock the wheels up skidding 2-3 at the end of my driveway.

Second issue is the brakes feel weak. Sitting at a stop light the pedal will work its way to the floor board. If your sitting at the stop light pumping the brakes the pedal will get stiffer.

I took the front wheels off and the pads are 1/2 life or better & the rotors look real good with no grooving.

Im thinking its either the master cylinder or a brake line that is bad? I don't see any leaks while under the truck. The truck is from northern NY! so all of the brake lines are rusted but don't seem to be wet from leaks.
 
I had a similar problem, peddle would just go to the floor and sometimes they worked decent. It was the antilock thing at the master cyl. Replaced and problem solved. To diagnose mine at first I just bypassed it with a coupler.
 
My ABS & parking brake light stay on the dash at all times.
 
First thing take a needle nose vise grip and pinch off the rubber line going to the rear axle than hit the pedal. Hard as a rock the problem is back there. Still soft? Move to the front lines and repeat. It's easier to diagnosis before you buy and throw parts at it.
 
Red_Rattler said:
First thing take a needle nose vise grip and pinch off the rubber line going to the rear axle than hit the pedal. Hard as a rock the problem is back there. Still soft? Move to the front lines and repeat. It's easier to diagnosis before you buy and throw parts at it.
Click to expand...

and with the truck being as old as it is be ready to replace said line afterwords.
 
Well you don't slam on the pedal and you don't have to put much pressure with the vise grip to pinch the line off but whatever you think. If the line is that brittle in the first place it's would blow at any second under normal driving conditions.
 
Last edited:
Not really,but whatever you think
on edit: dont take that in a smartass kinda way, I was just repeating what you said jokingly.
If the line is as old as the truck then it will be brittle. Once you squeeze it together you are pushing it the opposite of which it has being working all along.Therefore possibly making a weak spot or possibly causing it to collapse internally. Thats all Im saying.
 
Last edited:
on a simpler note, might bleed the brakes just to make sure there isnt any air in the lines? given that you bought it that way who knows what the previous owner may or may not have done...
 
First thing that needs to be done is to check the entire system for leaks and make sure its all good, such as brake wheel cylinders,shoes,calipers etc.Then try bleeding the brakes. From the sounds of it he might have an issue with the hydra boost or master cylinder. But,without being able to see it it makes it more difficult to diagnose.
 
I'd be willing to bet the rear brakes shoes are extremely out of adjustment. I'm not saying thats all that is wrong but I'd do that first.
 
Thanks for the ideas guys. Im going to try pinching off the rear line & checking the rear shoes.
 
9 LIVES said:
My ABS & parking brake light stay on the dash at all times.
Click to expand...

This could be caused by a vacuum leak, I know mine was. Quick way to check is see if cruise control isn't working and if defrosters stay in that position even when the switch is on something else (ie: feet)

If either of those are a symptom it is more than likely a leaking/disconnected vacuum line.
 
Last edited:
ChuMaDD said:
This could be caused by a vacuum leak, I know mine was. Quick way to check is see if cruise control isn't working and if defrosters stay in that position even when the switch is on something else (ie: feet)

If either of those are a symptom it is more than likely a leaking/disconnected vacuum line.
Click to expand...

a vacuum leak would cause a hard pedal situation.
 
JJeepyjohn said:
a vacuum leak would cause a hard pedal situation.
Click to expand...

It will throw the ABS/Brake light

After he checks the other stuff already mentioned, I would recommend checking the strength of the pump. You need to pull off all of the vacuum hoses and plug the ports. Get a gauge and test the vacuum pump to see if it is actually the problem. After that re-install one item at a time and re check for vacuum and how fast it bleeds off when shut down. I have had cracked lines, leaking reservoirs, bad brake boosters, and the vacuum splitting port itself cracks too. Its not always the pump though, so check everything before buying parts!!
 
CHuMadd, after your deletion and then repost. Yes,you are correct....IF. it has gone that far. But I doubt it has. Low fluid,bad sensor etc can set that light. He should start at the rear and check everything out. And don't pinch the line IMHO.at least not until youve check the shoes and cylinders.
 
Update: I put a reman master on.....that didn't help. I put a new one on and it didn't help either. While coming to a stop if you pump pump pump rapidly the brake pedal gets hard as steel and won't stop the truck until the pressure bleeds off the pedal (within 4-5 seconds).

I didn't get a chance to bleed the air out of the brake lines yet seeing that 3 of the 4 air bleeders broke off! That's going to be fun to fix :doh:

I took the rear hubs off and all looked well in the rear. Other then the adjuster is seized up.
 
have you made sure you don't have any vacuum leaks? I almost wrecked my 94 dodge pulling a gooseneck because of a small vacuum leak, lost most of the brakes in stop and go traffic. found a hole in one of the small vacuum lines a few days later.
 
You must log in or register to reply here.
Back
Top