1993 W350 brakes

[snowman9980]

I already know the answer to this, but I am going to post here so you guys can confirm my diagnosis.

1993 W350, get in and when you first push the pedal down it goes down quite aways ( but not to the floor) with minimal braking effort. If you let up on the pedal and push it back down right away ( pump them up kinda of) the pedal is all the way at the top with good braking effort. At first I thought maybe the adjusters went to h3!! So rebuilt the back brakes last fall with new wheel cylinders and hardware but that didn't make any difference.
The brake line going to the ABS valve is getting pretty ripe so I was thinking on replacing it and ditching the abs valve.

Am I on the right track?

 

[RWherley]

I bypassed my ABS valve and I think it helped but the pedal still has more travel then newer trucks.

 

[NIsaacs]

So rebuilt the back brakes last fall with new wheel cylinders and hardware but that didn't make any difference.

It sounds like they need a maual adjustment. How far does your e-brake pedel go down when you set it? Any more than 1/3-1/2 way down, the rear brakes are loose.

Nick

 

[snowman9980]

It sounds like they need a maual adjustment. How far does your e-brake pedel go down when you set it? Any more than 1/3-1/2 way down, the rear brakes are loose.

Nick

Manual adjustment has been done, it was done when I rebuilt the brakes with new hardware. That is what I thought originally, that is why I rebuilt the rears, I thought the adjusters were froze and not working.

I live in N Michigan. Ebrakes are not used here. If the did work you would not release them....the salt we use on roads up here pretty much takes care of E brake cables

 

[SnoKing]

I think when I had my 93' I replaced the ABS valve thingy and it helped somewhat. But I have to say it did not have good brakes, and I finally just brought a 2001.5!!! I did really like the looks of the 93 with 16.5 rims and tires, plus the Warn front bumper. See the bug defector, I took in off after 5 years or so and the washer water start hitting the windshield!

Funny I have owned 5 pickups over the years, maybe the next one will have a back seat!

SNOKING

#ad

 

[NIsaacs]

Manual adjustment has been done, it was done when I rebuilt the brakes with new hardware.

Sorry, I am going to harp on this a little. They have now had time to "seat", I would check them again. Dodge pickups are known for the rear brakes to not self adjust. Do you have any wear in your pedal/master cylinder linkage? Has the master cylinder or brake booster ever been replaced? If one or both have been at some time, the booster rod to master cylinder adjustment might be off.

Nick

 

[snowman9980]

Sorry, I am going to harp on this a little. They have now had time to "seat", I would check them again. Dodge pickups are known for the rear brakes to not self adjust. Do you have any wear in your pedal/master cylinder linkage? Has the master cylinder or brake booster ever been replaced? If one or both have been at some time, the booster rod to master cylinder adjustment might be off.

Nick

I will check into that. the master cylinder has been replaced, but that was almost 18 months ago. I will still check into that and I will look at the adjustment too. I am going to be under there replacing that line anyway. I pull a gooseneck trailer with it and I don't feel comfortable with that line being is ripe as it is

 

[DVolk]

Have you replaced the hardware ? some times they just wont catch the stars any more . also do you pump your brakes when you back up at all ?, thats the way they adjust .

 

[DMcLeod]

I may be off here, but I had a similar condition (sort of pumped the brake to get firm pressure), also the brake light would illuminate when holding the brake for a bit. I found the booster was leaking vacuum and replaced it. I also replaced the master cylinder because it was a leaky mess. Have you checked vacuum?

 

[CircleS]

My two cents. On my 93, they just will not self adjust. A regular manual adjust keeps me with good pedal.

 

[tclark]

I bet it's the vacuum that is making the pedal travel/effort change. Is your vacuum pump leaking too? These trucks you have to self adjust the rear brakes no doubt about it. Good luck.

 

[snowman9980]

Manual Adjust is NOT the problem. I replaced ALL hardware last fall on the rear including wheel cylinders and the manual adjustment was done at that time. I don't run the truck in the winter anymore so it has less than 300 miles on that adjustment.

Never thought about checking the Vac. I am assuming I tee into the line going to the booster with a vacuum gauge? What is the spec?? How much should it hold?

 

[RSchwarzli]

Its your booster or vacuum feed (pump, hose, etc). Willing to bet your booster if I had to take a guess.

I replaced my booster and it solved the issue. Note though, don't replace with a NAPA booster. They crap out in a year. Get Mopar or talk to mysterman for a rebuild kit.

 

[DMcLeod]

When I check vacuum, I start by checking the pump; that means, don't tee into the line, but hook the vac guage directly to the line coming off the pump (i.e. pull line off booster and hook directly to guage. Make sure line is in good shape - mine was cracked). Spec is 8.5" minimum, 25" maximum vacuum. After you know your pump is working fine, then move on to the next components until you are certain there are no leaks, or until you find a leak. An easy spot to check system vacuum is to pop the line off the sensor just beneath the drivers side hood hinge (looks like hockey puck) and plug your gauge in there. I don't know if this is your problem, but it's easy enough to check your vacuum system, and then you can rule that possibility out!

 

[DVolk]

That was my next guess , im afraid to think about how much mopar units are .

 

[snowman9980]

I have a wedding this weekend, but memorial weekend is D Day so to speak. I will make all the checks and report back with my findings

 

[snowman9980]

******update******

Well, I did all the vac checks and everything tested to spec. I ran a new rear line and bypassed the abs valve and that solve my problem. Pedal is right to the top and nice and firm every time you hit it.

 

[HHhuntitall]

I see a lot of these older trucks where the ABS unit gets overlooked in several ways... the actuator never gets used unless you panic stop regularly, and it often traps air, not letting it out, even when bled properly. Bypassing doesn't seem to hurt anything, and definitely gives a better pedal!!