Brake Booster Size

[crash-harris]

I've knocked a lot of things of the to do list and now I want to do something about the vacuum brake booster for the winter. Eventual plan is hydroboost, but I don't have the time or money to throw at it in the present.

I have a 10.1" diameter vacuum booster in the gas truck (which I got for a F350 with a7.3L IDI), but the other booster listed for a 1990 Ford F350 7.3L is a 10.7" diameter. Anyone know which size is stock for a crew cab dually diesel? I can get another 10.1" diameter booster free on warrenty.

 

[LCAM-01XA]

Does what you have now stop decent? If yes then get another one like it under warranty. Them boosters were like $100 last time I had to mess with one, not the kinda money I wanna drop on something that's eventually getting replaced with a hydro anyways.

Also, Ford did upgrade their boosters as time went by. Therefore, I would look into boosters for a '96 truck - those would be the latest and greatest that will directly bolt up to your firewall.

 

[crash-harris]

The one I have now has bad seals in it and bleeds off pressure. The other truck with the 10.1" diameter booster stops fine, but also weighs about half of what the dually does.

 

[jaluhn83]

The smaller diameter one may be correct - from what I can tell there is a larger single diaphragm used on the lighter trucks and a slightly smaller diameter double diaphragm unit used on the heavier ones.

If what you have works just get another one of those.

 

[crash-harris]

If the smaller one is a dial diaphragm (description doesn't say) then I'll just get another one of those. I just wasn't sure since I have the smaller one in the lighter gas truck that I put in with the 1 ton swap, but I haven't messed with the one in the crew cab and that's the one that's failing. Don't want another incident like last winter before I got the diesel. The 1 ton booster in the gas truck got moisture in it and failed on the coolest day/night we had and I basically had no brakes. The diaphragms even froze up and stuck, letting the rod slip through them. I can hear the one in the crew cab diesel hissing with my foot on the pedal.

 

[crash-harris]

Just checked the autozone descriptions again and they are BOTH dual diaphragm boosters.

 

[IDIoit]

I don't know if it's stock or not, but my 87 F350 had a 8-9" power booster.
Stopped great! Even with 3 tons+ on the back

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[crash-harris]

I'll definitely go the free route then.