My Spungy brake pedal

[JCasper]

Last night I had to go out and play Musical trucks, campers, and boats.



At one point last night I moved my Father-in-laws 07 MegaCab, his 05, and his 03 and everyone of those trucks has a very solid brake pedal. Then I get back in my truck to park my trailer and go home and my brake pedal is soft.



My truck always seems to stop fine, but something isn't right. If I ever have to hit the brakes really hard, the pedal will become solid for a while but then gradually go back to it's normal soft feel.



I don't know what's up, I just thought I would throw it out again.



I have had the brakes bled once before last year and it didn't change a thing.



Could it be something with the hydroboost unit?

 

[wcjp]

Are you sure the brake lines are in good shape? Could be a defective brake line. If you swap them, try braided stainless lines. Factory soft lines have some give. Braided stainless lines don't expand. I experienced better braking on my 96' CTD when swapped for braided stainless. Also, you mentioned the lines were bled last year. Did this include the fluid in the master cylinder? The contaminants in brake fluid compress while brake fluid doesn't compress.

 

[AMerrill]

The only time I had that happened was when the master cycled had went bad had to rebuild it that was on my old 79' Ford that is the only ford I will ever own that was the last good year ever.

 

[jelag]

The most common issue with a soft pedal with drum rear brakes, is out of adjustment rear shoes. If you haven't mechanically adjusted the rear shoes, you should do this before bleeding.

On 4 wheel disc brakes its air in the system, and next is the left caliper mounted backwards on the right side and vice versa... or the brake hose and bleeder locations have been swapped... hose is always connect lower on the caliper than the bleeder... . Bleeder is always on top to allow the air a way out. .

We suggest that you use a hand held vacuum pump, with a catch container to bleed the brakes and do so until the air bubbles cease to come down the line.

We have sold some power brake units but following the old one's through the process all that we have received as a core would have functioned, meaning that they where changed out without cause (read nothing wrong).

Brakes are usually straight forward and what we usually find is incorrect diagnosis, air in the system, or something someone else has not correctly put back together.

Hope this helps.

 

[JCasper]

I am going to put bleeding the brakes on my long list of things to do. Hopefully that will help. I paid the dodge dealer last year to do it, but I'm wondering if they actually did it. I don't trust them at all.



How about one of those brake bleeder kits that goes on the top of the master cylinder. Takes out the need of a pedal pusher. Any suggestions on a decent price one of those that will only get used once in a while?



Thanks for the help so far.

 

[rbattelle]

How about one of those brake bleeder kits that goes on the top of the master cylinder. Takes out the need of a pedal pusher. Any suggestions on a decent price one of those that will only get used once in a while?

I have the "Power Bleeder Pro" on this site. Has worked flawlessly for me.



My only complaint is it's a huge PITA to attach it to the master cylinder. Takes me forever to get a tight seal. Once I do, however, bleeding is a piece of cake.



Ryan

 

[LMcCary]

jelag has some good info. One more thing though. Check your wheel bearings for slack. As slack will cause the piston to be forced back into the caliper, which takes more pedal to refill it.

 

[JCasper]

I have the "Power Bleeder Pro" on this site. Has worked flawlessly for me.



My only complaint is it's a huge PITA to attach it to the master cylinder. Takes me forever to get a tight seal. Once I do, however, bleeding is a piece of cake.



Ryan

Looks like a nice kit. I think I've seen them before.



I don't know if I want to spend $90 on it though. I may try the old fashioned way first.

 

[Glen Pratt]

I bought a brake bleeder from K-D Tools similiar to this:
#ad

I used a turkey baster and sucked all the old brake fluid out of the master cylinder and then filled the master cylinder with fresh brake fluid and proceeded to bleed all 4 wheels. I continued to bleed until they was absolutely no air bubbles what so ever and there was fresh fluid at each bleeder screw. My brake pedal was very firm after that, not that it was spongy to begin with. Brake fluid absorbs water. My Jetta TDI service manual calls for flushing the brake fluid every two years.

 

[JCasper]

I bought a brake bleeder from K-D Tools similiar to this:

#ad


I used a turkey baster and sucked all the old brake fluid out of the master cylinder and then filled the master cylinder with fresh brake fluid and proceeded to bleed all 4 wheels. I continued to bleed until they was absolutely no air bubbles what so ever and there was fresh fluid at each bleeder screw. My brake pedal was very firm after that, not that it was spongy to begin with. Brake fluid absorbs water. My Jetta TDI service manual calls for flushing the brake fluid every two years.

So this unit sucks the fluid through, instead of pushing it through?



I have heard that brake fluid should be changed every couple of years. I paid the dealer to do it last year, but I am wondering if they actually did it.

 

[Glen Pratt]

Yes. The K-D Tools one I have seems to be discontinued. It was under $80. 00. Here's a link to the one above for a $100. 00
Mityvac MV6830 Brake Bleeder - Brake Tools

 

[JCasper]

I have the "Power Bleeder Pro" on this site. Has worked flawlessly for me.



My only complaint is it's a huge PITA to attach it to the master cylinder. Takes me forever to get a tight seal. Once I do, however, bleeding is a piece of cake.



Ryan

I bought a brake bleeder from K-D Tools similiar to this:

#ad


I used a turkey baster and sucked all the old brake fluid out of the master cylinder and then filled the master cylinder with fresh brake fluid and proceeded to bleed all 4 wheels. I continued to bleed until they was absolutely no air bubbles what so ever and there was fresh fluid at each bleeder screw. My brake pedal was very firm after that, not that it was spongy to begin with. Brake fluid absorbs water. My Jetta TDI service manual calls for flushing the brake fluid every two years.

So between these two units, What do you all think is the better one?



It looks like one uses vacuum, has to be hooked up at each wheel, and one uses pressure, just hook to the master cylinder and crack each valve open at the wheel.

 

[Glen Pratt]

I don't know. Like I said I have the pneumatic/vacuum type and it's worked well for me. The Mity Vac MV6830 looks like it can be used both ways.

 

[JCasper]

I don't know. Like I said I have the pneumatic/vacuum type and it's worked well for me.

Good to hear.



So it sounds like you just push the hose over the bleeder screw, crack it and turn on the vacuum.

 

[Glen Pratt]

You got it.

 

[rbattelle]

I've got a Mityvac hand-pump that I've tried and didn't like (for brake bleeding).

I found it too difficult to get a good seal around the bleeder screw.

What I like about the Motive pressure bleeder is you set it up on the master cylinder, fill it with fluid, pressurize it, and then just go around and open each screw. Very easy.

Only problem is getting a good seal on the master cylinder.

Ryan

 

[Glen Pratt]

This is the one I have:
#ad

KD Tool 3578 Brake Bleeder - Brake Tools
On the rear bleeder screws I had a hard time getting a good seal, but nothing that a small piece of clear hose didn't cure.

 

[MyDiesel]

I have an 82 Corvette. I bought a lifetime brake bleed from Firestone in the next town. . None nearby. I had them bleed the breaks every time I was in town. They used a bladder on the master. The breaks would be fine for a short time, spongy by the time I got home. I hooked up the shopvac to each wheel cylinder, one at a time using a reservoir in between. Sucking the break fluid through works far better. The next time I stopped in at Firestone to tell them how to do it right. They told me they figured it out and had bought a venturi system to run off their air hose. I've always done my own breaks, rebuilt cylinders, ect. Never any problems bleeding until the Corvette.

 

[JCasper]

I have an 82 Corvette. I bought a lifetime brake bleed from Firestone in the next town. . None nearby. I had them bleed the breaks every time I was in town. They used a bladder on the master. The breaks would be fine for a short time, spongy by the time I got home. I hooked up the shopvac to each wheel cylinder, one at a time using a reservoir in between. Sucking the break fluid through works far better. The next time I stopped in at Firestone to tell them how to do it right. They told me they figured it out and had bought a venturi system to run off their air hose. I've always done my own breaks, rebuilt cylinders, ect. Never any problems bleeding until the Corvette.

Great info. Thanks for sharing the results from the two different methods.

 

[JeffBob]

I strongly recommend you park the truck and have it inspected by a certified technician. You may have suffered a primary hydraulic brake circuit failure! Do not operate or tow with this vehicle.



I Just experienced this on my 2005 3500 dually and it's not air in the lines or an ABS issue.



I flushed the entire system last year with DOT 4 fluid when i bought the truck, installed Hawks on all corners. This truck has always had a very, very hard, knumb pedal and i just assumed it was the vaacuum system due it being a diesel truck.



But this afternoon, making a stop from 35 mph appraching a stop sign, something failed in the brake system - it felt like something snapped - and the pedal went soft and can now be pushed to the floor and there's an audible vacuum leaking sound from the pedal cluster beyond 1/3 pedal travel.



It's not right.



I can find no evidence of a hydraulic fluid leak or falling reservoir level, but it sure feels like I'm bleeding the brakes every time i make an aggressive stop.



But i can engage the abs, and the pedal feel and modulation is, ironically, now excellent! As good or better than my BMW or my Porsche!



But something broke - maybe it's the inner wall of one of the (original) brake lines. Normally i put steel braided lines on my vehicles when i buy them, but i cut that corner on this one.



Alternatively, it's a bad master cyclinder or a bad vacuum booster or a vacuum leak.



But i have to assume the next failure in the link would be catastrophic brake loss. I'm taking it to Dodge for a diagnosis.