Rear disc brake conversion

classic Classic list List threaded Threaded
82 messages Options
12345
Reply | Threaded
Open this post in threaded view
|

Rear disc brake conversion

85lebaront2
Administrator
I am in the process of doing a rear disc brake conversion for a good friend, actually you could say best friend as we have known each other since 1972, raised kids together, both pursued the same woman, and as he put it "you asked first". We also both campaigned my 1966 GT350 in autocross competition, he bought the tires and I provided the car.

He has a 1995 F350, crew cab DRW truck similar to Darth, but with a Powerstroke Diesel. The kit he purchased from Circle Track Supply is pretty comprehensive and is offered in both Dana and Sterling versions, his is the Sterling which also encompasses the 1985-86 models. He purchased a used 4.10 traction-loc from Pete's Used Parts that came from the same truck a lot of Darth's interior and the Alcoa rims came from.

I will be adding pictures as it goes along, but the gist of it, it uses Cadillac Eldorado calipers with parking brake provision and rear rotors from a later E series with rear disc brakes and the internal drum style parking brake. These still take the same bolt circle as the pre-1998 F series. In order to clear the inner dual rim, the rotor is mounted on an adapter installed on the inside of the hub and retained by the original wheel studs. In order to fit on the pilot on this aluminum adapter, the original hole in the rotor has to be enlarged to fit as the rotor hole is 4.9" ID and the pilot on the adapter is 5.4"+.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Steve83
Banned User
Did he or you investigate simply swapping in a later factory rear disk axle?  It seems like what you're doing will be a lot more work & expense; both now, and later as the parts have to be replaced for normal wear.  With a stock axle, he could simply buy direct-replacement parts.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
Yes, and it is called "bolt circle change" the 1998 up super duty trucks use a metric bolt circle that is not compatible with the older trucks. Believe me I almost bought a complete 2000 SD rear till I found I would need two different rims, two front plus one spare and 4 rear plus one spare.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
The kit is made by a company named EGR Performance Brakes located in Statesville NC. It seems to be a very comprehensive kit, but there have been a few issues.

Here is the left side drum brake and hub, axle is upside down on my pneumatic frame lift as it sits on the pads by adding a scrap piece of 2X4 to get the pumpkin off the center and is fairly stable and at a convenient working height.



Here is the right side, brackets and caliper are installed, rotor adapter has been attached to the hub using the 8 9/16-18 wheel studs (remove them and reinstall with the adapter in place).



The issues so far have been:
(a) really should recommend wire brushing the back side of the hub after removing the studs
(b) parking brake cable has an angled penetration on the backing plate
(c) rotors were not machined from the 4.9" ID to the needed 5.465" OD of the adapter

Brake cable solution (provided by Glen at EGR brakes) was use an angle cut piece of 1/2" EMT conduit, this can be seen in the right side pictures.
Rotors will be taken care of Monday when LCN Machine shop reopens.
I wire brushed the right side hub before assembling it.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

ArdWrknTrk
Administrator
In reply to this post by 85lebaront2
If the E350 axle was the right width, with the right spring and shock mount spacing, it might be easier.

Having to cut it up and weld it back together, 100%, is easier said then done.
And then there's the matter of axles made to fit....
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Gary Lewis
Administrator
Bill - What's the reasoning behind the move to disc?

I grant that Big Blue's brakes are marginal with a load on, but suspect they aren't working properly and hope that the move to the bigger '95 F350 brakes in front and hydroboost all 'round will solve that problem.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
John Gleason's truck has never had decent brakes, I think the decision maker for him was while we were working on the house in NN, and rather than get his Corvette out after backing his truck and trailer in since the restaurant we were going to closed fairly soon, I suggested he just drive Darth as I was there on the street. First corner he damn near put us both through the windshield. I told him, that's what the brakes are supposed to feel like. He's had his back to the same shop in Poquoson 4 or 5 times over brakes.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Gary Lewis
Administrator
You don't have hydroboost on Darth, so it is just that the brakes are working correctly?  Couldn't all be the big rear brakes, right?
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

ArdWrknTrk
Administrator
There's a LOT of friction area in a 12x3.5 drum!
If they are adjusted right and not covered in diff lube or glazed they will work well.

Compare that to the swept area of a pair of pads, and note only very little of THAT area is out at 6" from the axis of rotation.

Higher line pressures help, so maybe a smaller master cylinder, but there's only so much you can do about the laws of physics.
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Gary Lewis
Administrator
That's sorta why I'm asking the question.  It seems to me that properly functioning drum brakes would more easily be able to stop the rotation than disc brakes just given the leverage, not to mention the swept area.  

Given the reports I've read on hydroboost, and the braking capability of Darth, then.....
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

ArdWrknTrk
Administrator
Look at trucks that carry REALLY heavy loads.
You don't see triaxles and semis with discs very often, do you?

If I had a set of shoes and a set of pads and compared the area, using the same mu, you would really think.
Then factor the reduction in lever for the disc pads and you'd wonder how a truck stops at all.

Of course, in a couple of years when we have BEV's we will call it charging our battery....
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
In reply to this post by Gary Lewis
No, I do not have Hydroboost on Darth, just the booster from the 1990 parts donor with a new (at the time) MC. I do still have the rear load compensator.

Jim, on the tractor-trailers, the air brakes are a lot simpler to make and service as a drum system. The emergency system is a second spring applied, air released, actuator on the back of the service actuator. That way if the air system is damaged or in any way not working correctly, the brakes (usually rear on the tractor and all on the trailer) are engaged. Loads of fun to manually release too.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

ArdWrknTrk
Administrator
This post was updated on .
I've seen, and experienced what happens when an air brake system catastrophically loses pressure.
I've never tried (not do I want to) unlocking the brakes.

We have pneumatic releasing brakes thanks to George Westinghouse.
He made his millions from rail cars.

https://en.m.wikipedia.org/wiki/Westinghouse_Air_Brake_Company

https://en.m.wikipedia.org/wiki/WABCO_Vehicle_Control_Systems
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
Further progress or lack thereof on the disc brakes.

First item, rotors would not fit on the adapter pilots, holes were 4.9" ID, adapter pilots 5.46" OD. Had to wait till Tuesday (8/5) to drop them off. Picked them up Wednesday AM and put the right side together in the afternoon less seal so I could check runout. Runout was .007", desired .005" max. Thursday tried old trick, marked rotor and adapter and turn the rotor 180°, runout is now .002". Pressed in new Motorcraft seal (Gary, read TSB 94-19-24 before working on BBs rear hubs) and assembled the completed hub and rotor and adjusted the bearing play.

I went to mount the right caliper and found this:


I did some other playing around with a prototype Left Eye Blind Racing and Fabrication sent me for trial. It at least lined up with the rotor fairly well, but had some interference with the rim (courtesy of Pete's Used Parts in Newport News VA). The rotor needs to be at least another 1/4" inward to guarantee clearance.


Looking at the EGR instructions, the picture they have shows what appears to be a much taller "hat" on the rotor which would fit with the further in location of the caliper.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Gary Lewis
Administrator
Bill - You have the patience of Job.  Those problems would drive me bananas!  (But I may be doing some of that with Sky's Off Road on the RSK, so...)

Anyway, is it fair to say you are halfway there?  I hope the view is worth the climb.

On TSB 94-19-24, while I don't have it on the site I probably have it in hard copy form.  However, The Diesel Stop has it via that link.  But I'm not sure that Big Blue qualifies for it as BB is an '85 and the TSB says 1986 - 94.  And while BB's Sterling has been changed to the long pinion, I doubt anything was done to the hubs.

But I'll check it out when I have to go into the hubs.  Thanks!
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
Gary, I have it and the one that preceded it in pdf form and can email them to you. The tool kit for the Sterling says "1985 1/2 special tools. The reason you will want to check the TSB is it addresses the leak problems with the rear wheel seals on the full floating hubs. Seal design was changed from a standard style where the rubber seal runs against the axle tube (first change was to a "multi-lip" design) the final update went to a seal package where both the part in the hub and the part on the tube are fixed and the actual seal is encased in metal and pre-lubed. The actual seal is available from Amazon in the Motorcraft PN. I will get you that PN also.

Keep in mind I have been dealing with these fun issues for a bit over 25 years.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

Gary Lewis
Administrator
That's good info, Bill.  And thanks for the pdf's.  I'll get them added to the site as soon as I can so all can use them.

The second one doesn't say it replaces the first one, but it would appear to do so.  Right?
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
Yes, it seems that way. I got real proficient at tearing down and resealing the left side on Darth's original axle.

FWIW, changing the gear set to the later long pinion design does not necessitate hub disassembly, just pulling the axles far enough back to get the differential out.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

ArdWrknTrk
Administrator
In reply to this post by 85lebaront2
Swapping to the Scottseal saved my sanity and a lot of brake shoes.  
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
Reply | Threaded
Open this post in threaded view
|

Re: Rear disc brake conversion

85lebaront2
Administrator
Ok, update, spoke with Glen at EGR brakes this morning, they are machining a pair of deep top hat rotors, the ones the U-Haul E350 DRW and motorhome E350 cutaways use. This should move the calipers in far enough to clear the wheel. Hopefully the caliper mounts will work without any changes. He is sending a "call tag" for the other rotors. I will post the outcome once everything is done.
Bill
"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 1994 Taurus LX
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413
12345