'86 C30 Dually Rear Disc Conversion

[da_raabi]

I know there are a few threads out there on this topic, but I just wanted to put together an all-in-one dually disc conversion thread. I just placed an order for the first batch of parts I need, sometime next week I will order the next batch. As I place orders I will update this thread with part numbers etc. As this truck is my daily driver I will hopefully be able to get the whole project done fairly quickly, maybe on a weekend. Based on what I have read it should be possible, particularly with the help of my wife. So here are the part numbers and links for what I have ordered so far:

ROTORS
Brand: Wearever
Part Number: YH141049
Qty: 2
Price Each: $38.99
Store: Advance Auto
Link: Wearever YH141049

CALIPER - LEFT
Brand: Fenco
Part Number: SLC530
Qty: 1
Price Each: $26.46
Store: Advance Auto
Link: Fenco SLC530 - Unloaded Reman Caliper

CALIPER - RIGHT
Brand: Fenco
Part Number: SLC531
Qty: 1
Price Each: $26.46
Store: Advance Auto
Link: Fenco SLC531 - Unloaded Reman Caliper

PADS
Brand: Wearever
Part Number: Frontline Severe Duty FLD153
Qty: 1
Price Each: $38.47
Store: Advance Auto
Link: Wearever Frontline Severe Duty - FLD153

WHEEL STUDS - OPTIONAL
*Note I needed a couple new studs anyway, so I got the longest available (3-17/32")
Brand: Dorman
Part Number: 98741.1
Qty: 16
Price Each: $1.99
Store: Advance Auto
Link: Dorman 3-17/32" Wheel Studs

All in all after discounts I got all that for $183.49. All I need now is the brackets from diy4x, disc/disc master cylinder, and flex lines (numbers to come). As parts roll in and I place additional orders I will update. So far my math shows the complete swap coming in at $400.49. Not bad for an HD rear disc brake setup. Note that the rotors, calipers, and pads came off the front of an '86 K20 Pickup with the JB7 (13") brakes. I'll post more as I think of it.

**UPDATE**

Went ahead and ordered the backing plates from diy4x:

Backing Plates
Brand: diy4x
Part Number: 01700k
Qty: 1
Price Each: 96.21
Store: diy4x.com
Link:Dana 70 Dually disc conversion brackets

 

[towjoe]

I've got a 86 crew cab dually about like yours. I took the running gear out of a 10 lug chevy motor home and was going to use all it and the 19.5 wheels tires on mine. still haven't tried it yet, hate to ruin a good truck if it don't work out

 

[da_raabi]

Ok so I did a little research on my next issue. I have been trying to figure out how to meter the brake fluid correctly for a disc/disc setup. After extensive research I discovered the following:

Our trucks have 1 or 2 metering valves: all have a disc/drum proportioning valve on the front frame that both brake lines off of the master cylinder go to, and 1 tons have a "load level sensor/valve" under the bed. I looked up the inlet/outlet sizes of the existing forward prop valve and matched a disc/disc valve on Summit:

Designed to fit models with 4-wheel disc brake conversions. Inlet sizes are 1/2 in.-20 and 7/16 in.-24. Outlet sizes to front are 3/8 in.-24 and rear outlet is 9/16 in.-18.

SO. The result of that story is I will simply be replacing the existing proportioning valve on the front of the frame with a:

Proportioning Valve
Brand: Right Stuff Detailing
Part Number: pv72
Qty: 1
Price Each: 58.99
Store: JEGS on eBay
Link: http://www.ebay.com/itm/Right-Stuff-PV72-Proportioning-Valve-For-4-Wheel-Disc-Conversion-/400444184703?pt=Motors_Car_Truck_Parts_Accessories&hash=item5d3c55587f&vxp=mtr

ALSO I will be removing the load level sensor/valve in order to eliminate ALL possible brake restrictions. Since this is a totally non-stock setup I want to try and keep things as simple as possible. More info to come...

 

[da_raabi]

The big brown truck dropped off a couple (heeaaavvyyy) presents yesterday! First batch is here:

You must be registered for see images attach

I didnt realize just how big those calipers and rotors are!

 

[da_raabi]

Ok, I decided to go with stainless hoses for the three existing brake lines on the truck. I went with:

3-Piece Front/Center Stainless Brake Hoses
Brand: Russell
Part Number: 672310
Qty: 1
Price Each: 68.57
Store: eBay

I already had a set of brake hoses from a project I was going to do on my old Dog Durango that should fit the rears, so I plan to make those work and save a little $$.

If all goes well I will do this project this coming weekend!

 

[da_raabi]

In preparation, does anyone know if I will need to rebuild the hubs, or can I just reuse them as they are? They do not squeek or wobble or leak, will they be ok as they are?

While I'm at it, does anyone know how the hell to get the front rotors off of a dually truck? I cant seem to figure out how to get the dust cap off...

 

[da_raabi]

Well here goes... I get off work in an hour and then the tear-down begins. I'm doing one side at a time to help make things easier organizationally. This is going to be a TON of work, but I'm looking forward to it. Pictures to come!

 

[da_raabi]

Status: Failed

So everything was going great, right up until I went to install the calipers. It was at that point that I realized that the backing plates were a good 4-6 inches too far back from the rotors for the calipers to work... Apparently the Chevy 1 ton Dana 70s with the duallys have the drum backing plates mounted far further inward that others, so a simple "flat" backing plate would not do. If I had a 4" spacer between the stock welded-on bracket and the needed location of the backing plate I could have done it, but as I needed the truck for work I just rebuilt the drums and called it good... The stainless brake lines made a big difference though!

Suffice it to say this project was a complete failure, and Diy4x will be getting a phone call today, hopefully they can come up with a product that will work in the future. Unless I missed something HUGE, their dually brackets will NOT work on an '86 1 Ton.

 

[bucket]

Maybe Kurt accidentally sent you SRW caliper brackets?

 

[da_raabi]

Dunno, they look just like the ones in the picture. Honestly after I pulled everything apart I dont honestly know how you could make a backing plate work safely, like I said there was about 4 inches between where it was, and where it should have been. To make it work the bracket would have had to be huge! I wish I had taken a picture, but I needed to get the truck back together so I was in a hurry. I'll see if I can make a drawing of it, might help make more sense.

EDIT: I hope no-one think I'm bashing here either. I'd be the first to say that the parts I got were of the highest quality, and they were shipped very fast. I've got nothing against diy4x, I would buy from them again any day. It just so happens their part did not fit my application. Just wanted to clear that up...

 

[1984dually]

I've got a 86 crew cab dually about like yours. I took the running gear out of a 10 lug chevy motor home and was going to use all it and the 19.5 wheels tires on mine. still haven't tried it yet, hate to ruin a good truck if it don't work out

Did you ever try this? I have an 78 Barth that I have thought about doing the same thing. Has 4 whl disc(parting it out).

 

[da_raabi]

Ok I think I may have found a solution. Apaprently a rear rotor from a 2003 Express Van Dually should fix the issue. It is a very very deep rotor. There appears to be some question as to whether a 1/4 in spacer is needed between the hub and the rotor to make it perfect, but I'm gonna do some more research. More notes to come!

 

[89Suburban]

Good investigating.

 

[Jim Hensley]

what happened with this?

 

[da_raabi]

I never ended up going forward with this. I sold the brackets and rebuilt the drums. I wish I had stuck it out and finished the discs but... oh well. At the time I was living in an apartment and working out of a storage unit sooo.... Yeah it was tough to take these projects on when you had to drive the vehicle home at the end of the day.

Now that I have my own place I may try this again, but the 100% rebuilt drums work just fine.

I think my research was on the money though. The express van rotors would likely work with the diy4x brackets. It would definitely be worth a try!