im looking to upgrade to some brakes for my 90 idi. ones that dont suck *****. ive got a new vacuum pump, flushed the fluid, new pads and my brakes still wont lock up to save my life. full weight on the brake pedal and it still rolls. any ideas? im runnin 37x13.5x18's and going to throw on some 40x13.5x18 soon. i also haul a lot so im trying to get a system that will double my performance.

 

Hydroboost...

 

i was thinking more along the lines of new calipers or larger disks.

 

Runnin that big of a tire I'd go hydro boost from a 97 superduty and disk brakes in the rear. What the heck could you haul with a truck sittin on 40's? Is your trailer on 40's too?

 

Idont think you can get a big enough caliper to compare with a hydroboost steup.

 

Compare nothing, I'm saying run both, hydro & disk.

 

Well you would be running disc but what I meant you can upgrade and spend all you want if your using vacum it will not campare with a hydroboost power.

 

im not exactly sure how a hydro boost works, it has something to do with the power steering pump right?

 

Yes it replaces the vacumn booster with hydraulic assist powered by the power steering pump.

 

ya, my dads 02 has hydroboost. it does work very well. guess if i run it ive gotta fix my power steering leak huh? lol.... and i just bought a new dam vacuum pump for nothing! does the 460 fords have hydroboost in 97-98 as well or just diesel?

 

and ive got a 4" lift running 37's now with a 2" rise on my hitch and my trailer still noses down about 5%. when i finally figure out how to post pictures i will get around to that. ive got triple bellow air bags on the rear, helps give me an extra 5 inches lift when i need it and the trailer is almost where it needs to be.

 

At least one member used a chevy hydroboost setup If I remember right it was basically bolt on. I think he had to clerance the master cylinders two holes just a hair.
I have a system on a motor home that I am going to take a hard look at.

 

Hydra boost Ford E8TZ-2005-B
Pressure from hydraboost to steering box, passenger side fitting Ford

F4TZ-3A714-A
Pressure from PS pump to hydraboost, drivers side fitting Ford F4TZ-3A717-A
Return line from hydraboost to PS pump, drivers side nipple Ford E8TZ-3A713-B

Expect to spend about 500 if you go to Ford, these parts were originally installed on a 97 F Superduty (F450) and are a bolt on swap.

You also have to get a power Steering pump with two return lines, I got one at Advance Auto for the same truck but don't have the part number handy.

And after that swap, if you have any questionable brake lines, metal or rubber, upgrade them as well, because you will blow them out.

A couple weeks ago I had a car try to run me over and I slammed the brakes on.
And split a new metal brake line open about a foot long.
The tires stopped instantly even though I blew the line, but I was only moving about 25 MPH at the time.

What gears are you running in the axles with tires that big?

 

not sure the gears. no gear ratio tag on the rear end. i dropped the diff oil but didnt check it while i was there. 5spd w od id guess my my rpms ive got 3.73's

 

3.73's and big loads with 40" tires, better get a couple boxes of U joints.

I broke enough with 235 tires behind a stock 6.9.
Now with a modded turbo 6.9 and 285 tires, driveshfts last about 2 years, U joints last about 4 months.

4.56 gears with 40" tires would be about the same as 31" tires (235/85) and 3.55 gears.

On a 90, my guess is you have either 4.10 or 3.55 gears.

Give me a speed and RPM in 4th gear and I can tell you what gears you have now.
Also has the speedo be corrected for the tire size change?

Going from the stock 31" tires to 37" tires have created an error in the speedo reading.

235/85-16 tires with 4.10 gears would run 59 MPH at 2000 RPM in 5th gear.
Running 37" tires on the same setup at the same RPM in overdrive would be 71 MPH.
Jump to 40" tires, 2000 RPM in overdrive would be just shy of 76 MPH.

Don't forget, double the braking performance will mean you have to run double the brake line pressures.
So brake lines and hoses will be under rather extreme pressure.

Driveline and brake components have to run at 128% of the stock load to be even with what it had with stock tires.
Figure 2,000 PSI brake line pressure stock, with 40" tires that has to be 2,560 PSI to be even braking force.