the speedo works!!and a few hydroboost questions

[94f450sd]

well i dont know how i did it but on the cab swap i am doing i used a 93 gas cab and 94 automatic diesel wireing on an 88 F350 with a 5 speed.i dont know how i managed to do it but the speedo is working .dont know if its right or not but atleast it works.i can reprogram the PSOM later if needed.i dont remember it haveing a sensor in the rear end though but it does have rear abs so it might have it.


now i also swapped in an f450 hydroboost set up.the brakes sucked to begin with.but now they seem to work good except that if you go to do a panic type stop the pedal goes straight to the floor and all of a sudden locks all 4 wheels up.if you hit it normally it stops fine but feels like there is no pressure in the brake system.is this normal for the hydroboost/f350 master cylinder combo?if not what should i be looking at?

 

[icanfixall]

On my hydroboost in my Chevy C30 1 ton you can push the peddle all the way down to the floor but it will go into the bypass circut. Start the motor and while parked in the driveway push the brake peddle till it stops going down. Now continue to push it. It makes a hissing sound and gets easier to push. Thats how mine has worked for almost 30 years. I even changed out the booster and it still works the same.

 

[towcat]

rich-
I don't know how to explain it but every hydro has its own temperment. Many work like how you describe yours. There's a couple of factors involved. One is the PS pump. If it is marginal, it will do as you describe. The other is the little can on the right side of the hydro. If the can is working properly, there should be no sinking feeling. It is a pressure accumulator. If there is no nitro charge inside then the PS fluid has nothing to "preload" the system. Bottom line is yes, the pedal will give you the scarry feeling as it gets near the floor, but if the truck gathers its braking system up and turns on the Whoa.....prepare for loose objects in the cab launching.

 

[ttman4]

explain it TC...???

explain it

TC, Uhumm....explain it.....Atavar.
How's you always manage to come up with the best of 'em!
no wonder I need glasses...

 

[towcat]

TC, Uhumm....explain it.....Atavar.
How's you always manage to come up with the best of 'em!
no wonder I need glasses...

ummmmm....all I can say is her pic says it all
here's one more teaser;p
Mel is prolly gonna banish it over to GGG...

 

[ttman4]

nooooo

Mel is prolly gonna banish it over to GGG...

No he won't. Ther're IDI related.....she huntin the Crescent for 'ya, ain't she??
If he do, then I'll mozzy over there. No cover charge after hours....
I been run out of some classy, top-of-the-line places before

 

[Full Monte]

The hydroboost system doubles the pressure in the brake lines. It doesn't fix other brake problems that may exist. If the system has been well bled, check your rear drums (not sure if your model has them). If it has drums, it's critical that they be adjusted correctly. If the travel to grab is too far, the hydraulic system will run short of volume before the brakes grab, and the pedal goes to the floor.