Dually Brakes

[SCOTI]

I've been looking up parts info for the brake system on the dually because the master cylinder is DEAD. Looking @ the front rotors, they're pretty scarred & I doubt turn-able. I'm not one to replace just one worn part when everything appears of similar age & condition so I was getting ideas on costs for the rotors, calipers, & flex lines too.

As I was searching, I keep seeing a 'severe-duty' option. I'm guessing this was fleet type trucks (wreckers, ambulances, & similar). My assumption is these parts are just a HD version that will interchange w/the standard trucks (89 model FWIW).

Can anyone confirm this or share further insight?

[Tx Firefighter]

I'm watching this Scot. Be sure and update us with anything you figure out. I've been wondering the same thing for my project truck.

[SCOTI]

Originally Posted by Tx Firefighter

I'm watching this Scot. Be sure and update us with anything you figure out. I've been wondering the same thing for my project truck.

Will do. Diggin' the hay buggies BTW. They seem to be getting better after lessons learned.

[Tx Firefighter]

I appreciate the words about the buggies. The added financial boost sure helped Christmas this year.

I've been working on an older dually I have lately and taking a break from building trailers. My 94 dually has a hurt big block in it (blown headgasket and cam going flat). I limp it around but there's no way it will pass emissions next year so I'm trying to rebuild this older truck and get away from all that. That's the one I've been researching brakes for.

[SCOTI]

Originally Posted by Tx Firefighter

I appreciate the words about the buggies. The added financial boost sure helped Christmas this year.

I've been working on an older dually I have lately and taking a break from building trailers. My 94 dually has a hurt big block in it (blown headgasket and cam going flat). I limp it around but there's no way it will pass emissions next year so I'm trying to rebuild this older truck and get away from all that. That's the one I've been researching brakes for.

I recall you had a 78 CC/flat bed right? I'm guessing the 'severe-duty' stuff was for fleet vehicles destined for wreckers, small school buses, & ambulances. I would assume the parts are interchangeable much like Lt-duty 1/2 ton 1" rotors are w/the HD 1.25" version. The question is, like the 1/2 tons, do they utilize a different spindle?

[sailed2japan]

Here's some pics of discs off of a P30 Should be The HD stuff.

[sailed2japan]

The spindles I know will bolt on to the upper and lower ball joints. I used a couple of the control arms off this suspension to re-build my C20's front end after I wrecked.

[Tx Firefighter]

Originally Posted by SCOTI

I recall you had a 78 CC/flat bed right? I'm guessing the 'severe-duty' stuff was for fleet vehicles destined for wreckers, small school buses, & ambulances. I would assume the parts are interchangeable much like Lt-duty 1/2 ton 1" rotors are w/the HD 1.25" version. The question is, like the 1/2 tons, do they utilize a different spindle?

Yes, same cab and chassis. I started into it for my winter project, but yesterday I ran across an 87 SWB truck for 500 bucks. I'm really struggling with not buying the 87 and cleaning it up for a driver. I think 87 is the best year for square bodies due to the EFI, and they make super daily drivers.

Originally Posted by sailed2japan

Here's some pics of discs off of a P30 Should be The HD stuff.

The brakes in the pictures are way more beefy than either my 78 cab/chassis truck or my 84 crew cab donor truck. Way more beefy...

[Jonboy]

Scot, send me the VIN and I will see what I can find out on monday. Home today, less 4 teeth.

[Tx Firefighter]

I have a pair of dually spindles in my shop I can measure if we can find someone with the heavy duty spindles to measure theirs and we can compare.

[sailed2japan]

Yeah, if you post some pics and measurements, I'll compare them to what I have.

[SCOTI]

Tx,

The calipers pictured look like mine. When you said . . ....

The brakes in the pictures are way more beefy than either my 78 cab/chassis truck or my 84 crew cab donor truck.

Could you elaborate how they are "more beefy"?

[Tx Firefighter]

Lemme go out to the shop with my camera to see what I can find. I'll be back in a few minutes.

[Tx Firefighter]

These pictures are the brakes off a donor truck I bought awhile back. I think it's either an 84 or 85 Crew cab truck. The parts appear the same as the pictures posted above. However, the reason I bought these parts is that they are beefier than the ones on my 78 dually. It's outside the shop in the dark though, so no pictures of those parts tonight.

[SCOTI]

Well, I got the master cyl installed & bled the brakes. It stops now but not much better than before.... @ least the pedal doesn't collapse now.

The front pads don't look paper thin but don't appear new either. It does look like the pads were swapped w/nothing done to the rotors. My guess is the rears are in worse shape because of the apparent difficulty of a rear brake job. I say 'apparent' because personally I've never done rear brakes on a dually but have been digging for tech info. IMO, the rears aren't doing much if anything right now which is why it's taking so much brake effort to stop this lil' red tank.

I just went back outside for final clean-up, crawled under the front again & confirmed the front calipers look just like these....

[N2TRUX]

Since you sound like your going to go through the entire system, I would look at what Praise Dyno Brakes has to offer- LINK A good friend of mine went through lots of pads on rotors on his F350 until he bought a set from Praise. The cryogenic treated brakes are a HUGE improvement over stock.

[sailed2japan]

rear breaks on the dually aren't too difficult. The big thing is you need to pull the axle shaft. once that is done pull off the nut for the hub/drum assembly and pull the drum. All in a days work...or 2 ays if you do both sides.

[SCOTI]

Originally Posted by sailed2japan

.....you need to pull the axle shaft.... pull off the nut for the hub/drum assembly.... pull the drum. All in a days work...or 2 ays if you do both sides.

Exactly why many would opt to just roll w/it as is. That's some effort vs. just replacing front disc pads (remember, the rotors weren't replaced or turned from the looks of them).

[sailed2japan]

Personally I don't think it's Hard at all. It only takes an extra 15 or 20 minutes over any other drum break job. Now I rarely touch my rear breaks because it doesn't seem like they wear out...EVER! They must be magic

[sailed2japan]

Scoti, what dod your brakes look like? Are they the same as these? I'd like to see the other version for future reference.

[83burban]

I put the severe duty on my c10 suburban with the heavy duty chassis. Here is the difference:

The outside diameter of the severe duty application will remain the same (in my case - 1.25") The difference between the heavy and severe duty lies in the thickness of the gap with the ribs. The two sides are thicker in a severe duty application (so the gap is thinner between the two sides).

Another difference is in the chemistry of the metal. I believe that the severe duty uses more iron in the mix - thus making the parts heavier at less resistant to warping from braking and less prone to wearing down as quickly.

Hope this helps

[sailed2japan]

Well brakes on a dually and a C10 are two totally different animals. That's good info for the 1/2 tonners, though.

[jltait]

I saw a write up concerning upgrades to k30 hydro-boost using the P-series parts. The author claimed far superior braking performance, unfortunately I cannot find the article now. It was on another forum (coloradok5) and I never subscribed to the thread. Might be a good place to look though.
JLT

[sailed2japan]

Hydroboost is a far superior system to vaccum boosted brakes. I'll never go back to them in a truck especially.

[SCOTI]

Originally Posted by sailed2japan

Hydroboost is a far superior system to vaccum boosted brakes. I'll never go back to them in a truck especially.

Before I got this truck, I expected the exact same thing.

I was very surprised during that 1st test drive @ how ineffective the brakes were (it takes some serious pedal effort to stop this thing). I think Jonboy was equally surprised @ how much better the brakes were in the 74 vs. this dually (judging from the look on his face the 1st time he touched the 74's brake pedal as we braced ourselves on the dash ). That comparison told me there was need for a thorough inspection & expected maintenance.

My buddy Matt had a good point when we discussed concerns on Saturday. He feels we should just adjust the rears so they're @ the correct drag/tension & swap on some new front rotors/pads. We'll go from there. I'll get some pics before the rotors are swapped.