I have a friend with a problem...

[rumblecloud]

On my Facebook feed, I am a member of a Ford Ranger group. One of the guys there s having a squuirrely issue with his brakes and am wondering if it would be ok for me to relate his issues here? I'd be kind of a middleman unless he decides to post it himself -- I did invite him to join. Please let me know.
Basically he has rebuilt his brake system and has no pedal when the truck is running. Hard pedal when truck is off. It's a 94 Ranger - like mine.Thanks in advance. R

 

[rusty ol ranger]

On my Facebook feed, I am a member of a Ford Ranger group. One of the guys there s having a squuirrely issue with his brakes and am wondering if it would be ok for me to relate his issues here? I'd be kind of a middleman unless he decides to post it himself -- I did invite him to join. Please let me know.
Basically he has rebuilt his brake system and has no pedal when the truck is running. Hard pedal when truck is off. It's a 94 Ranger - like mine.Thanks in advance. R

Sounds like a blown booster.

Have him pull the vaccum line off it and see if they stiffen up

 

[rumblecloud]

Hey Rusty..Thanks for your response. He has done a lot of different checks and taken the logical corrective measures, but I didn't want to detail them until I got an okay to even post this request. I will compile it in a sensible order and repost when I get it together. Obviously it would be much easier if he just did himself and maybe he will jump in later. He has visited here before not sure why he doesn't want to/or just hasn't joined. He'd get a much better response here than FB for sure. Stay tuned...


EDIT: I will ask him to do that...thank you

 

[Uncle Gump]

No offense to Rusty... but if unplugging the vacuum line at the booster results in a firm pedal... it proves nothing. We already know the pedal is firm not running. It sounds like the booster is working just fine to me.

Two things come to mind for me...

Some air still in the system

Rear brake shoe adjustment

You're OK to post this question here @rumblecloud

We're always willing to help out a Ranger owner...

 

[rusty ol ranger]

No offense to Rusty... but if unplugging the vacuum line at the booster results in a firm pedal... it proves nothing. We already know the pedal is firm not running. It sounds like the booster is working just fine to me.

Two things come to mind for me...

Some air still in the system

Rear brake shoe adjustment

You're OK to post this question here @rumblecloud

We're always willing to help out a Ranger owner...

Actually thats a good point.

But id still bet on a booster. Even with rear brakes way out the pedal shouldnt hit the floor.

Did 94 havE ABS?

 

[Uncle Gump]

RABS

 

[rumblecloud]

Dammit...thought I posted this yesterday. The RBS was what I was thinking also...

Here are some more details:
Replaced Master Cylinder
Booster
And a one brake line
Bench bled the master
Claims good fluid flow from all four bleeders - bled properly farthest away to the closest using the buddy system
Calipers are installed with the bleeder up
Good vacuum at the booster

Things I've mentioned:
RBS proportioning valve but no response on that
And obviously air still trapped in the system at the rear

Can the proportioning valve cause this (brake to the floor when running.)
that's all I have for now.


Thanks

 

[Uncle Gump]

Did he mention if the brakes still work... but a really low pedal?

 

[Uncle Gump]

Also... when the rear brakes are properly adjusted... engine off... the pedal should have a small amount of free play at the top but be solid as a rock. If the pedal does any amount of travel to get solid... the rear brake adjustment is off.

 

[Uncle Gump]

I should also add that if you get good fluid flow at the rear bleeders the RABS Valve is flowing.

 

[rumblecloud]

I should also add that if you get good fluid flow at the rear bleeders the RABS Valve is flowing.

Thank Uncle. I checked in today and there has been no progress. It may be on the back burner. I will be sure to follow up here as soon as I get some feedback on what's going on. Thank you for your continued interest.
The ABS dash light i not coming on. But dang it something's f'ed up and there aren't too many things that can cause it. I'm betting on air still in the system cuz I know how hard it is to get it all out.

 

[ShhhhhDougsHere]

I'm just a novice around here.

However I put my bet on air in the lines still.

If it was me I would bleed the breaks while the truck is running.

 

[rumblecloud]

He re-bled the brakes with the truck running AND pulled the vac line from the booster when running and the brake pedal got hard.

In response to Gump's earlier posts:
The pedal goes to the floor - no resistance at all.
Good flow to the rear.

Just seems like the booster id f'ed up?

 

[Uncle Gump]

Ive fixed a lot of brakes over the years... I've only had to replace a few boosters... and never for this symptom.

What i have done to correct this condition is fix a bunch of leaks... bled a bunch of air and adjusted a bunch of drum brakes. I even found a couple flex lines that balloon with fluid pressure.

So I'll ask this again... engine off... apply the brakes with some pretty hard force... is the pedal at the very top... firm and holds there with that force applied?

I'm just failing to see how a booster can pull the pedal all the way to the floor and not apply the brakes and stop pedal travel on a brake system that is properly bled and adjusted.

 

[Uncle Gump]

There was also a case I read on here that the really low pedal was caused by the firewall flexing.