oldmisterbill
Grumpy Old Man
From the voice of experience "tread softly and carry a light shoe" Or just "hang on"
Infamous Sinking Brake Pedal
- Thread starter Fordfleet
- Start date
From the voice of experience "tread softly and carry a light shoe" Or just "hang on"
BigRigTech
Diesel junky
If it locks up too easily I will install an adjustable prop valve...I will have weight in the dump box so I don't expect any issues.
Double-S-Diesel
parts seller
I battled on ebefore, ended up being the rabs assembly
94turboidi
Full Access Member
So I wonder what the superduty trucks have on the frame is it basically the same rabs assembly or is it a improved setup and matched for the disc brakes? I would like to have disc brakes down the road and I wonder when people have problems with the rabs if its because of half a zillion miles on the odometer or a bad design?
yARIC008
Drives really slow
That new 1 1/4" master cylinder really isn't a good idea actually. I did that modification and with the engine not running and no vacuum to the break booster you can barely stop! Basically you lose your hydraulic advantage. That master cylinder is designed for calipers with larger pistons.
One time when my vacuum pump decided to fall off due to me not tightening the bolts properly, i shut the engine off, and of course had no vacuum too, i about died. The brake pedal was rock solid and I basically just had to steer to safety, couldn't hardly stop.
But if you like that sort of thing, you're good then
Is it possible the new 1 1/8" master cylinder you got before was defective? Did you prime it properly before install?
One time when my vacuum pump decided to fall off due to me not tightening the bolts properly, i shut the engine off, and of course had no vacuum too, i about died. The brake pedal was rock solid and I basically just had to steer to safety, couldn't hardly stop.
But if you like that sort of thing, you're good then
Is it possible the new 1 1/8" master cylinder you got before was defective? Did you prime it properly before install?
94turboidi
Full Access Member
That new 1 1/4" master cylinder really isn't a good idea actually. I did that modification and with the engine not running and no vacuum to the break booster you can barely stop! Basically you lose your hydraulic advantage. That master cylinder is designed for calipers with larger pistons.
One time when my vacuum pump decided to fall off due to me not tightening the bolts properly, i shut the engine off, and of course had no vacuum too, i about died. The brake pedal was rock solid and I basically just had to steer to safety, couldn't hardly stop.
But if you like that sort of thing, you're good then
Is it possible the new 1 1/8" master cylinder you got before was defective? Did you prime it properly before install?
I had the same idea in my head at the difference in bore size loosing some of the power making it feel more like manual brakes. I just did a hydroboost swap and used the f450 master cylinder. I am going to put my old master cylinder back on because I have noticed the brakes are nothing like what others have posted with a hydroboost swap. Their good but not what I was expecting. Another thing is the f450 master didn't have the cruise control deactivation switch on it so my abs light is on. I am going to switch back as soon as it feels like summer again.
Double-S-Diesel
parts seller
the f- superdutyds dont have a rabs valve with the or rear abs
This is from the 89 manual, but is pretty much how all RABS unit works, there is 4 downloads once you get there. Some how I lost some of the pages, if you need more, I don't have the manual with me just now.
If you would have difficulty bleeding the RABS, unscrew the large nut/plug on it, in behind it is a piston and spring, remove the spring but leave the piston in, replace the nut, start the engine and pump the brakes several times, apply the brakes, open the bleeder valve on the RABS, close bleeder, release the brakes, then replace the spring. This should give a full brake peddle.
BE SURE AND BLOCK THE WHEELS BEFORE DOING THIS.
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If you would have difficulty bleeding the RABS, unscrew the large nut/plug on it, in behind it is a piston and spring, remove the spring but leave the piston in, replace the nut, start the engine and pump the brakes several times, apply the brakes, open the bleeder valve on the RABS, close bleeder, release the brakes, then replace the spring. This should give a full brake peddle.
BE SURE AND BLOCK THE WHEELS BEFORE DOING THIS.
I put a stronger, but same size spring in mine...
Wolfer
Registered User
I took mytruck into shop for complete brake job they could not get front brakes to bleed no pedal and air in lines after bleeding. It is a 94 f-350 IDI Apparently in 94 there was a trailer brake controler option and it had been dripping and when stepping on brake pedal when bleeding front brakes it put air into lines and pumped brake fluid out. Since it was higher than all other brake lines it would not bleed out air at first just fluid but brake pedal went to floor after bleeding. Had mechanic going nuts. This controller was OEM.
79jasper
Chickenhawk
It may have been dealer installed, but those were no where near being oem.
Sent from my SM-G892A using Tapatalk
Sent from my SM-G892A using Tapatalk
Wolfer
Registered User
That is what I was told it was 24 years ago. I will take your word for it. Just informative in case someone ran into that problem. Maybe I can help someone else. Thanks for correcting me.
79jasper
Chickenhawk
No big deal.
You can still get those systems.
Many have removed those because of leaks.
Sent from my SM-G892A using Tapatalk
You can still get those systems.
Many have removed those because of leaks.
Sent from my SM-G892A using Tapatalk
321fordguy
Registered User
hey adrianspeeder can you tell me are you fixed or not have same concern as you
