Hopefully some one has done a rear disc brake conversion that can help. I am in the process of swapping rears in my 98 e-350, the new rear has disc brakes, I need to know what changes are needed, specifically the ABS or proportioning valve (if their is one)

 

greetings TE. i did the disc brake conversion on my 95 e350 but used aftermarket brackets and eldorado calipers. in my case i changed the master cylinder to a disc brake version from a later model van to correct the issue of the drum brake residual valve causing the disc brakes to drag - typ drum resid valve rating is 10psi and disc is 2psi. that required changing the power booster as the new master required a different bolt pattern and sealed to the booster differently. changing the booster required redrilling holes thru the firewall to mount it as well as changing the brake pedal. i chose to solve that part by having my rebuilder take the back half of the 95 booster and mate it to the front part of the late model booster thus giving me a bolt it piece - cost $50 for his labor.

i hose to do nothing about the proportioning valve issues as i planned to upgrade my front brakes which would restore the balance to more or less neutral. i did take a 1200 mile trip in the van w/ stock front brakes and the new rear discs. it stopped great!! it did feel like i was getting more stopping power from the rear, but then i had set up the rear drums real loose to keep from eating them up so i may just have more or less returned to what i should have had all along.

i had no lockup issues when stopping as hard as possible w/ the abs defeated (pulled the fuse) so i chose to button it up and drive it. it was probably the second best upgrade i have made to the van and was worth every penny and bit of time.

hope you are tossing in an axle w/ an lsd - i did mine at the same time. another good upgrade.

hope this helps
neil

 

Thanks Neil !
This makes a big difference.......This is the first I heard of the residual valve. I searched around a little and found that I can possibly just remove this valve from the Master Cylinder so the discs dont drag. Did you try that ? I will find out today if I can remove it. If this works my MC will still have a smaller bore (1 1/4) than the newer one (1 5/16) (1 3/8 on F- series super duty) but I might just bleed the brakes and see how it works, and whether it is safe or not.

Thanks- Tom

 

I'm considering the axle/disk up grade on my 1995 as well. From what Iv learned the non metric 99 and 2000 are the axles we want.

Is Neil's method the way to go? Or can you simply remove the residual valve like TEMiller asked?

Thanks!

 

I'm going to be doing the 99 E350 disc brake rear diff swap into my 89 E350. I'm going to swap in the matching 99 E350 Master cylinder and am going to install an aftermarket adjustable proportioning valve.

Running the 99 E350 master will give me the correct bore sizing and correct residual pressure valve for the rear disc brakes.

And the aftermarket adjustable proportioning valve will let me manually adjust the rear brakes to where I want them.

 

I swapped a sterling 10.5 from an f series (even bigger piston calipers than the e-series) and all I did was remove that residual valve on the master. Bled it out and drove it, I liked it never felt weird to me. I drove that for a few years and never had a problem. Only thing with the f-series rear was adapting the parking brake cable, but if you are using the dana 60 van rear then you shouldn't have a problem.

 

I never said it would feel weird. Removing the residual valve from a disc/drum master will just give you a little more pedal travel before the rear brakes start working. And the master cylinder sizing will basically just change pedal travel and effort. What you don't want to do, like neil 95 e350 mentioned way back in 2010, is run the disc/drum master with the drum brake residual valve and rear disc brakes. If you do the rear brakes could drag.

The F-series 10.5" will have a different bolt pattern then the vans. How did you get around that? How did the spring perches of the F-series rear line up? Or did you need to cut off the originals and move them?

The rear parking brake cables will have to be changed no matter what. The disc brake rears have different ends on them.

 

I just bought the wheels that fit the metric bolt pattern and swapped a d-60 in the front so everything matched.
The spring perches needed to be cut off and repositioned as the van springs are wider and pinion angle was steeper on the f-series.
I have just recently changed out the vacuum booster for hydro-boost.

(the other way around the bolt pattern is to use front rotors and brakes for an 2wd f-series if you don't want 4x4)

 

Ok, thanks for the info. I was pretty sure the vans spring perches were wider on the van. I'm probably going to have to adjust my pinion angle when I do my swap. I'm swapping out the rear club wagon springs for some new 10 leaf cargo van springs. So the rear of the van will sit quite a bit higher. But I'm hoping I can correct the pinion angle enough with tapered shims. But I'll have to match up the pinion angle to the manual transmission and transfer case, staying 2wd just adding it for another low range, I'm swapping in.


I was going with the van D60 rear to keep it as close to a bolt in deal as possible. And I've got a whole collection of rims that fit the van pattern. But I do like the idea of the stronger/larger rear diff with better brakes. What year trucks had the 10.5's? is it just any of the 99-current trucks? And is there any difference between the F250 superduty diffs and the F350's? I know my way around the 97 and older stuff but haven't had much experience with the 99+ Superduty's. The other deal is what was the tallest gear offered on the Superduty's? My current gears are 3.55's. And I wanted to keep that gear ratio because it's a great highway gear. So far the tallest SD gear I've found is a 3.73. I'm not going to be running an OD transmission for a while so I didn't want to go to low on the gears.


I don't think the newer rotors/hubs would fit the older spindles. Aren't the newer truck sealed hub bearings? If they are I don't think they would fit the older spindles with the old style wheel bearings. Which means I'd be stuck either seeing if a machine shop could redrill the pattern on my 89 rotors. Or carry multiple spare tires and run two different style rims. Maybe I'm better off sticking with the dana 60!

 

For the record I wouldn't recommend going with the 10.5 rear from the super duty unless you were doing the 4x4 upgrade. A d60 with the disc brakes from a newer van would be the way to go if you just wanted to upgrade to rear disc.

Shims will work. 10.5 came in 99-up super duty. 250-350 same diff but the 250's had bolt on shock perches and the 350's had welded on. Not sure if that is exclusive, but when I was searching thats what I noticed.

You may be right about the gears. The 3.73 works well with a 34-35 inch tire.

I cant remember exactly but the 2wd stuff is all conical bearings, not sealed hub. Im pretty sure the bearings are the same so the SD rotors would bolt on the van spindle but I think it was the caliper bracket that had a slightly different bolt spread. You would have to get the SD 2wd spindles (same ball joints)
I had most of the stuff to do it 2wd but ended up returning it and getting everything to do the 4wd swap. It was years ago so I cant remember all the particulars.


Couldnt you change to a lower gear and use an OD trans? What is the benefit of having the low range?

 

The 10.5" is sounding like more trouble then it's worth for the few benefits it has over the D60.

My tires are going to be in the 31"-32" range. I need to stick with the load range E tires, for the hauling/towing I do.

I like the NP435 Grany low 4spd transmission add that to the 3.55 geared rear and it's basically a poor man's OD. I'll have the grany low to get the heavy loads moving but still have the top end highway speeds because of the 3.55's.

Eventually I'm going to be swapping to 4.11 gears once I swap in an Advance Adapters Ranger OD unit. But right now that's not in my budget. I'm going to be spending enough on the transmission swap, new rear springs, rear diff, rebuilding the entire brake system and front suspension & steering, electric cooling fans, all new gaskets, seals and timing set in the engine, fabricating a new exhaust system with a Hooker aero-chamber muffler and installing Autometer Mechanical gauges. Oh yea and I can't forget about the $800+ in new BFG AT's for it.


The low range is good for pulling really heavy loads slowly. But the main reason is it helps a great deal for backing a trailer up a hill. That and I already had the 4x4 transmission and transfer case sitting in my garage.

 

I'm looking at a 2001 dodge D80 since my cummins keeps tearing up my D60.

Good to know that removing the residual valve works.

 

The sole purpose of the residual valve on the MC is to maintain about 10 lbs of pressure in the lines going to the drum brakes. Without that valve, the pressure in the brake lines is about 2 lbs. That pressure is enough to apply the disc brakes with minimal foot pressure on the pedal because there are no retraction springs in a disc brake caliper.

On the other hand, drum brakes have to have springs to keep the shoes from rubbing constantly against the drum. The 10 lbs pressure counteracts the retraction spring action and allows the drum brakes to apply with the same pedal pressure that actuates the discs.

Removal of the residual valve for a 4 point disc system works because discs don't need as much pressure to activate them.

And since 90% of braking is done by the front brakes for most vehicles, including our vans, you really don't need to increase the MC bore size. Doing so merely increases the pressure applied at the wheels, with a concomitant increase at the pedal.

 

bringing this back .....1996 E350 (ABS on 4 wheels )
I`m swapping my whole diff with a complete 1999 E350 diff.....
the 99 has discs brakes , otherwise same thing ..(gears, measurements etc.)


On my 96 master cylinder ,there is an adapter at the back mc output ..
Is this the residual valve ? if so, if I switch to a regular adapter ,should it solve the problem ? ( my mc is new )

thanks


Dan ,

 

That's what I plan on doing on my 89 E350.

Yes that is a residual pressure valve on the rear outlet port on the master. I plan to remove it from my master cylinder when I do my rear disc brake diff swap. I am also adding an adjustable proportioning valve in my rear line. But since mine is a 89, I don't have all the ABS crap to deal with. I was just going to use the 99 master but found out it won't fit my booster.