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OBS F350 brakes

AKnate

Icehole
Joined
Mar 5, 2022
Member Number
4908
Messages
1,124
Any ideas why most of my braking is on the front, to the point it gets them smoking hot?

Rear pads were replaced last year, and I adjusted it this spring which slightly helped.
They engage when tested with ass in the air. And park brake holds the truck fine.

Pedal travels normal, and effort is normal. It isn't spongy.

It's borderline scary trying to stop with a load. More of a stopping suggestion than STOP
 
My rear brakes were going out of adjustment, turns out the lever was slipping over the top of the shoe
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Do you have the 2.5" or 3" shoes? What year rear wheel cylinders? How old is the flex line down to the rear? Ever had the prop valve apart? Does your RABS work?
 
On my 95, the rabs valve was restricting flow to the rear brakes. I deleted it and got a whole lot more brake power. You might try bypassing it for diag purposes.
 
Tryloff said:
On my 95, the rabs valve was restricting flow to the rear brakes. I deleted it and got a whole lot more brake power. You might try bypassing it for diag purposes.
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This can be sketchy sometimes.

I ran no rear brake limiter on one of my chevys and the rears were insane. But it was a light in the ass street drw.

Did you try bleeding the rears just to verify that the fluid is flowing properly?
Once again on one of my chevys i had a prop valve fail and wouldnt reset just plugging the rear brakes off all together.
 
total newb said:
This can be sketchy sometimes.

I ran no rear brake limiter on one of my chevys and the rears were insane. But it was a light in the ass street drw.

Did you try bleeding the rears just to verify that the fluid is flowing properly?
Once again on one of my chevys i had a prop valve fail and wouldnt reset just plugging the rear brakes off all together.
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I wasn't recommending to remove it. You're right, in the rain you had to plan your braking or else you would end up backwards. I was mainly suggesting to bypass to see if that where the restriction was. If they still don't work, he could move on to prop valve. If they work great then he needs a rabs valve. I'm pretty sure those are pricey now.
 
For by passing the rabs, there's a big nut in the front. Take that nut off and pull the spring out. Had to do that on my truck. But it was giving me a soft petals
 
I had luck in past replacing rabs with adjustable proportioning valve, seemed to help keep rears from locking up
 
This is the reason I put E-350 brakes on.

Guys say hydro boost with drum brakes makes a world of difference.
 
It's a 97 cab and chassis. Single cab 4wd diesel with 12ft dump bed. Weighs around 8500lbs empty, around 19000lbs loaded.

I think it's 3" shoes but can't remember for sure.

I reused the old hardware as it was fairly new (I redid brakes due to hub seal leak)
 
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I may remove the ABS deal if it has it. I don't recall ever seeing one, but can't say I looked specifically for it.

Can't recall if it had a rear proportion valve or that was the 97 F Super Duty I'm thinking of. Whichever i took the rod off and turned it to full power to the brakes.
 
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Find a flat straight stretch of road and put it reverse and lock the brakes up HARD 10-15 times see if that helps.

Or, rust.

Wait, rear PADS, then you adjusted them?

Shoes as in drum?
 
Etyler2 said:
Find a flat straight stretch of road and put it reverse and lock the brakes up HARD 10-15 times see if that helps.

Or, rust.

Wait, rear PADS, then you adjusted them?

Shoes as in drum?
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Yeah, drums. I meant shoes.

Backing up should adjust them, but so does turning the star wheel with a brake spoon.
Had them to where it was barely grabbing with no brakes.
 
AKnate said:
Yeah, drums. I meant shoes.

Backing up should adjust them, but so does turning the star wheel with a brake spoon.
Had them to where it was barely grabbing with no brakes.
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It will still get way better slamming reverse.
 
Etyler2 said:
It will still get way better slamming reverse.
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All that does is run the adjuster arm on the star wheel and maybe move it a click, if at all... unless I'm missing something
 
AKnate said:
It's a 97 cab and chassis. Single cab 4wd diesel with 12ft dump bed. Weighs around 8500lbs empty, around 19000lbs loaded.

I think it's 3" shoes but can't remember for sure.

I reused the old hardware as it was fairly new (I redid brakes due to hub seal leak)
Click to expand...

I did hydroboost on my '95 f350 and it stopped a whole lot better. Manual trans did most of the speed control.

At that weight, I'd lose the RWABS. Confirm you have 1-3/16" wheel cyls.
 
AKnate said:
It's a 97 cab and chassis. Single cab 4wd diesel with 12ft dump bed. Weighs around 8500lbs empty, around 19000lbs loaded.

I think it's 3" shoes but can't remember for sure.

I reused the old hardware as it was fairly new (I redid brakes due to hub seal leak)
Click to expand...

19,000lbs loaded? The F350's were only rated at 10,000 gvwr, so you're rolling around at nearly twice the gvwr?
 
ZSK said:
19,000lbs loaded? The F350's were only rated at 10,000 gvwr, so you're rolling around at nearly twice the gvwr?
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Just like every other F350 doing work. It's a C&C truck, I think frame is beefier than the pickups, but I may be wrong.
 
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AKnate said:
Just like every other F350 doing work. It's a C&C truck, I think frame is beefier than the pickups, but I may be wrong.
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They rivet some shit to the bottom to make it stronger. IMO it's a net negative because it promotes rust but maybe not where you are.
 
AKnate said:
It's a C&C truck, I think frame is beefier than the pickups, but I may be wrong.
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It is beefier. The pickup frame is a noodle. Should have rivetted strapping along the bottom, and stiffener plates on the sides. Have seen it 1st-hand before.... unless thats an extra-extra HD option on top.
 
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Lets be honest though, we dont use these trucks the way Ford intended. A tall straight rail will carry a ton of weight, but its not built to resist twisting on the trail, its built for a heavy load in the bed, on a mostly flat road. It primarily needs to resist bowing, not twisting.

That said, its possible frame stiffeners are an option based on GVWR or wheelbase. In the early 90s the F-Superdutys got beefy cast iron spring hangars instead of the cheap stamped steel hangars all the other trucks got, but didnt get double frames or bracing. Maybe the rails were thicker though??? Id bet the closer you get to 1997 the more they did to strengthen the frame, but i had a 2008 F350 C&C and it didnt get any crazy frame bracing either. Also, C&C trucks are 34" frame width whereas all the others are wider, and a wide frame rail spacing is better for spreading the load. So id expect a C&C frame to be beefier than its standard counterpart just because its narrower.


We're getting sidetracked here though.

For the 10.25 there were 3 brake options for SF, FF, and dually. 2.5", 3" and 3.5" shoes . Some of the low GVWR FF 10.25s may have still got the 2.5" shoes, however that shouldnt be the case in a 97.

I was asking about the wheel cylinders, and u2slow brought it up as well. Somewhere along the line Ford upped the wheel cylinder size on the 10.25. Im going to make a WAG and say 94 but im not positive, could be 92. I just know that ive got 3 trucks with the 10.25 and the older one got the smaller wheel cylinders. They interchange but not really, because Ford upped the size of the nut on the brake line that threads into the cylinder (from 3/8 to 7/16 IIRC) when they upped the bore size. But again, 97 C&C should have the big ones. Since were eliminating improperly working brakes, that leaves an old and failing rubber drop line, or an issue with the RABS valve.
 
reptillikus said:
In the early 90s the F-Superdutys got beefy cast iron spring hangars instead of the cheap stamped steel hangars all the other trucks got, but didnt get double frames or bracing. Maybe the rails were thicker though???
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Different frame entirely. IDK if just dimensions or thickness too. I can crack open a service manual if you wanna see shitty sketches of it
 
arse_sidewards said:
They rivet some shit to the bottom to make it stronger. IMO it's a net negative because it promotes rust but maybe not where you are.
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It was used on dirt roads the first ~7-8 years in Prudhoe and then firewood/lumber delivery since.
I bought it cheap from a friend who had bought it at Ritchie auction, but a near new flatbed on it and ran it for maybe 7 or 8 years, toward the end, was mostly just a yard truck.

He thought the engine was bad. Was gutless, like couldn't do 50mph at WOT.
Ended up being combo of plugged air and fuel filters from zero maintenance since it left Prudhoe and 2 weak injectors.

Had around 57k miles when I got it, I've put like 7 or 8k since. Lot of idle time though, like ~6000 engine hours (stayed running 24x7 all winter)
 
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