I was also told about the brake pressure limit valve on the master cylinder, never knew what that was. By eliminating that valve I should get full flow to the rear breaks, whereas with the valve it was limiting the drums pressure.
I love talking to idiots at the parts stores who don't know what they are talking about...
Any idea what the difference is between rear calipers for the SD "To 12/20/99" and "From 12/20/99" ???
Other than about $35 each??
Edit: Actually, the fronts look to be cheaper than the rears, might as well go with them, as long as they fit the rotors...
The difference is whether the caliper is on the front of the axle or the rear. I think the to 12/20/99 is one in front one in rear (these will be the same part number for both sides) and the from dates are both calipers in the rear of the axle and the part numbers should be different. The difference is where the bleeder screw is located for the correct orientation depending on location.
As for the pressure limiting valve I have never given it much thought. Might have to look into it for testing.
__________________ Tim
1997 F-350 CC 4x4 PSD Auto 260K
I will keep My Money, My Guns, My home and My Family. YOU KEEP YOUR CHANGE!!
I was also told about the brake pressure limit valve on the master cylinder, never knew what that was. By eliminating that valve I should get full flow to the rear breaks, whereas with the valve it was limiting the drums pressure.
Jim, you may want to keep that valve, it eliminates the rear brakes from locking up under hard braking. It's on both drum and disc applications.
Here's Ford's description:
The brake master cylinder fluid control valve regulates the hydraulic pressure in the rear brake system. When the brake pedal is applied, the full brake fluid pressure passes through the brake master cylinder fluid control valve to the rear brake system until the valve's split point is reached.
Above its split point, the brake master cylinder fluid control valve begins to reduce the hydraulic pressure to the rear brakes, creating a balanced braking condition between the front and rear wheels to minimize rear wheel lockup during hard braking.
The Valve:
I read that exact same thing, but this is missing from your quote:
"A brake master cylinder fluid control valve is used on all vehicles except those equipped with dual rear wheels, and the F-Super Duty."
So it's NOT on dually trucks, just single rear wheel '94 - '97 and NOT on SD trucks. So it must not be that critical if they eliminated it from dually '94 - '97 trucks. The dually's had larger brakes, too, so you'd think it'd be easier to lock them up. ???
I'll try without it, if they lock up at the track I'll put it back on...
As for the pre-'99 thing, might be location and mounting, but there are different part numbers per side.
Thanks!
__________________
'96 F-350 Reg Cab 4x4 PSD
'97 F-350 CC Short Bed 4x4 PSD
__________________
Pete in San Ramon
2005 F250 6.0 Lariat 4x4 CC Short bed (stock)
1997 F250 7.3 XLT 4X4 Reg. cab (stock)
1986 F250 6.9 XLT Gone but not forgotten
You could do the hydroboost conversion too. If you haven't already. Was that on the F350 DRW chassis also?
__________________
Pete in San Ramon
2005 F250 6.0 Lariat 4x4 CC Short bed (stock)
1997 F250 7.3 XLT 4X4 Reg. cab (stock)
1986 F250 6.9 XLT Gone but not forgotten
Jim,
I left that out on purpose. Apples to Oranges IMO.....didn't want to muddy-up the waters. The duallys have hydro-boost and double the tires on the ground...so they should be much harder to lockup. I can't remember but I think they are 4 wheel ABS too.
Another alternative is to install an adjustable proportioning valve on the rear brakes along with omitting the fluid control valve. Infinitely adjustable from full pressure to no rear brakes at all.....smoky burn-outs
Cuda,
FYI, OBS duallys did not have hydroboost, nor did they have 4 wheel abs. I've owned OBS duallys in the past...
But I'll go along with more tire to the ground and harder to lock-up, makes sense. Plus, I bet by nature the duallys haul more in the bed, and/or tow more which means more downforce on the rears, too. ??
I think 2 - 14" slicks have more contact area than 4 dually street tires, though.
We'll see!
Thanks for the great input all!
__________________
'96 F-350 Reg Cab 4x4 PSD
'97 F-350 CC Short Bed 4x4 PSD
Not sure but I am pretty sure they did have the hydroboost.
Now if the SD OBS's had disks why wouldn't most people doing this mod just use them instead?
Not sure but I am pretty sure they did have the hydroboost. Now if the SD OBS's had disks why wouldn't most people doing this mod just use them instead?
Ah, the F-450...Had rear disks, too if I recall...
Yes the F-superduty has hydro boost and rear disc on a Dana axle (ie won't bolt up to the sterling axle)
Quote:
Originally Posted by Neal 97 250
Not sure but I am pretty sure they did have the hydroboost.
Now if the SD OBS's had disks why wouldn't most people doing this mod just use them instead?
See my response to Jim in parentheses. It could be an option but it would be just as much work as the 99 and up swap but the OBS SD calipers have a less desirable slides for the calipers IMO. Also no parking brake option as the OBS SD has a drive line brake. It bolts up to a 4wd trans but in place of the t-case. I have only seen the OBS SD in 2wd so I don't know if they came in 4wd and what those did for a parking brake.
__________________ Tim
1997 F-350 CC 4x4 PSD Auto 260K
I will keep My Money, My Guns, My home and My Family. YOU KEEP YOUR CHANGE!!
Yes the F-superduty has hydro boost and rear disc on a Dana axle (ie won't bolt up to the sterling axle)
See my response to Jim in parentheses. It could be an option but it would be just as much work as the 99 and up swap but the OBS SD calipers have a less desirable slides for the calipers IMO. Also no parking brake option as the OBS SD has a drive line brake. It bolts up to a 4wd trans but in place of the t-case. I have only seen the OBS SD in 2wd so I don't know if they came in 4wd and what those did for a parking brake.
'94 - '97 F-Super Duty only came in 2wd, unless it was a special Marmon conversion...
Reason the Chevy calipers are more popular, is they are CHEAP and simple to do. $50 per caliper, with core charge, vs $125 per SD w/core. AND the bracket for the SD caliper is bigger, etc.
Not sure about the slides not being liked, I haven't played with it yet.
But I did pick up a SD front caliper and I have a pic of it next to the '80 Chevy truck front.
Holy Cow!! You'd think the Chevy was for a lawn tractor or something...
__________________
'96 F-350 Reg Cab 4x4 PSD
'97 F-350 CC Short Bed 4x4 PSD
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