Brakes! Brakes! Brakes!

[Deathvalleydog]

Just got my '69 C20! Driving it is great. And then I tried to stop..... Woah. Now I know what eveyone's been talking about --- drum brakes bad!

Obviously replacing the drums with disks is my first priority. But I'm on a super tight budget. What is the best cheapest way to go? Aftermarket? Manufacture's upgrade kit? Or canibalizing a latter model -- and if so, what is a good source for locating said parts?

Thanks!

[airdale94]

Just did this on my 68C20. Bought a front stub off a 81. They just cut the frame rails aft of the crossmember. And gave me everything. $150.

[glock35ipsc]

GM started using front discs on the 71 models, so any of the OEM parts off of an 71-87 (?) 3/4 ton should be good.

[Irishpilot]

The cheapest way to improve stopping is to flush the brake fluid and check the drums for excessive wear. If that is not good enough, then parts of a '71-72 and you will have discs. I highely recommend you get a master booster for the disks and it is really a night-and-day difference.

[Spray-Bomb]

I think drum brakes are fun

[cdowns]

cheapest route would be a comprehensive brake job to really see what you've got and maybe some driving instructions from somebody that knows how to drive vintage vehicles

[67mater]

I have 4 wheel drum on a 67 4x4. In it's former lif I drove it as manual brakes (made no adjustments at all) and yeah, it wasn't great. Now, I simply made a 1" slug so the pin from a 72 booster would push my 67 manual MC, all new lines, and fuild, front wheels cylinders and it's night and day. I attribute it almost exclusively to the booster, as I still have the half worn pads in there!! Truck stops awesome now!!

[thirdstreettito]

Originally Posted by Spray-Bomb

I think drum brakes are fun

Because when they brake you can make music!

[Longhorn Man]

Adjust and clean the drum brakes, and learn to stay off people's bumpers, and you'll be fine. No, they aren't ideal nor even close to perfect, but there are advantages to them.

[Sinister]

Try bleeding your system. I got drums on my '69 C-20 and stops just fine.

[Longhorn Man]

they aren't as good as disks... esp in stop and go traffic... however, the c/20 drums are friggen huge, and in proper form, are quite capible of stopping the truck. Remember, the speed limit was 60 - 80 MPH when these were built... they were designed to stop the truck, fully loaded, within federal standards, with drums.

[Deathvalleydog]

Originally Posted by Longhorn Man

they aren't as good as disks... esp in stop and go traffic... however, the c/20 drums are friggen huge, and in proper form, are quite capible of stopping the truck. Remember, the speed limit was 60 - 80 MPH when these were built... they were designed to stop the truck, fully loaded, within federal standards, with drums.

Well, my real problem is that I live near the top of the steepest road in the county and just to get to town is a 1400 ft drop over 2.5 miles. Going down is an adventure even in low gear with modern brakes, and people cook 'em all the time. You mentioned some advantages to the drums. I don't have much experience with them, but are they less likely to "fade" than disks? That would be a big one for me :-)

[Lippyp]

Nope drums are way more prone to fading than disks as they don't cool as well. I know a lot of the hot rod guys running drums do some clever stuff with the back-plates and little air scoops and drilling holes to get more air through and finned drums also help dissipte heat bit the fact is they're a damn great chunk of iron thats going to stay hot much longer than a vented disk.

[OLDIRON69]

I agree, wheel cylinders and new shoes and check your drums for heavy wear. If you completely replaced all your drum brake parts with new and drove it, you would be happy with the stopping power.

[Deathvalleydog]

Originally Posted by Lippyp

Nope drums are way more prone to fading than disks as they don't cool as well. I know a lot of the hot rod guys running drums do some clever stuff with the back-plates and little air scoops and drilling holes to get more air through and finned drums also help dissipte heat bit the fact is they're a damn great chunk of iron thats going to stay hot much longer than a vented disk.

Just what I was afraid of. That being the case I think discs, vented discs, are definitely the way I need to go. If I lost my brakes on the hill the only thing to stop me would be the wall of the feed store in town. It would be just like haulin' chickins down t'other side of Wolf Creek Pass. (I'll be amazed if anyone catches this reference...)

[Jet Blue 68]

I was using the "pump pump pray" system on my '68, it usually stopped well. A few lock ups and scares but no "accidents" Manual drum-drums... but now the master cylinder is going out. I am in a simiar situation, except I already bought spindles, rotors, calipers and a rearend from a 5 lug 71 model. Oh and power steering system (pump, bracket, steering box) Nice fellow threw in the booster, m/c and pro. valve too. Paid $250. I know I'll have to replace some parts that I bought, so now wondering if I shoulda bought a kit. Because now I want to go ahead and lower it at the same time. I may save about $100-200 if I use what I have though and rehab what I have... Good luck with your decision. Makin decisions has been the hardest part for me.

[Stocker]

Originally Posted by Deathvalleydog

It would be just like haulin' chickins down t'other side of Wolf Creek Pass. (I'll be amazed if anyone catches this reference...)

Wolf Creek Pass, way up on the Great Divide, truckin' on down the other side.... great song!!!

Back on topic, the front discs on my '72 are vented... I think discs from the front of any GM C/K20 will be vented, so they shouldn't be too hard to find.

[d10s69c10]

well you can do the 72+ conversion for rotors up front but it makes it 5 lug... disks in the back alot more work and no where near as cheap then you will have to get a new master cylinder because your stock one wont push enuff fluid. i personally like the corvette 4 wheel disk i think 1972 master cyl 1 1/8" its a beast.

[Deathvalleydog]

Originally Posted by Stocker

Wolf Creek Pass, way up on the Great Divide, truckin' on down the other side.... great song!!!

Back on topic, the front discs on my '72 are vented... I think discs from the front of any GM C/K20 will be vented, so they shouldn't be too hard to find.

Nice! Glad someone remembers that song.
Do they make a conversion kit for eight lug? I've got nice eight lug rims I'd like to keep but every conversion kit I've found is five.
(BTW are you on the CA side or the OR side of Jefferson? Or perhaps folks from the State of Jefferson don't differentiate?)

[Stocker]

Originally Posted by Deathvalleydog

(BTW are you on the CA side or the OR side of Jefferson? Or perhaps folks from the State of Jefferson don't differentiate?)

You're right, it doesn't much matter

Born & raised in Oregon, now living in NorCal. In fact, it's more like Oregon here than most parts of Oregon are!

[LEEVON]

4 wheel discs are nice, but there is nothing wrong at all with a disc/drum set-up. GM used rear discs on full size trucks a couple of years ago and now they are back to drums if that tells you anything.

Rebuilding drums is cheap, if you're on a tight budget then rebuild them with new wheel cylinders, shoes, springs, adjusters, and turn the drums. Put new pads in the front and turn the rotors if necessary. Flush the whole system if you're comfortable doing so (follow master cylinder bench bleeding to a T). If you're still not happy then check the booster. My '71 stops as good as my '08.

[Rooster's 67]

I have just completed a disc conversion on a 65 C20 (which is for all intensive purposes the same as our 67-72). We used front end components off of a 77 R20 (suburban for those not in the know) It had the 8 on 6 pattern. Tony with Texas Squarebodies sold us the front frame section (cab forward) for $150.

When doing this on a 67-72 you can swap the whole cross member and control arms, but the C/R 20 and 30's use the same solid bushings on the control arms so unless your bushings are bad, use your original arms.

You have to change the upper and lower ball joints to 73-87 C20 units to mount the spindles.

steering linkage is a little more fun. The tapers in the spindles are a different size on the later model stuff so either swap in a powersteering gearbox and all the steering components from a donor or you can use the factory steering from the 67-72's but you have to obtain the conversion sleeves from one of the vendors here on the board so you can adapt the 73-87 outer tierods onto the older linkage.

Keep in mind when converting to discs you also have to install a dual resivior master cylinder and a disc/drum proportioning valve. (front and rear are two seperate hydraulic circuits)

you will use brake hoses from your donor truck and they mount infront of the upper control arm not behind like our 67-72's. you may have to bend some brake lines.

Spence

[Lippyp]

Its not neccesarily about stopping power though. Whilst drums all round can be made to stop well they don't perform well under hard continuous use as they will fade as things heat up and gases build up under the shoes. I have manual drum/drum brakes and with a good healthy shove they stop pretty well although I am about to fit a booster. In this guys situatiojn with a long winding downhill run I'd go for disks anytime

Have a read up on fade here

http://en.wikipedia.org/wiki/Brake_fade

[Rooster's 67]

Lippy is very much correct.

The problem with drum brakes is their heat dissipating capabilty there is just not enough air flow through, over and around drum brakes to cool them enough under severe use. As stated earlier a lot of the hot rod/streetrod world has used finned rotors, holes drillled into the backing plates with air scoops, and I have even seen drums drilled on the hub surface to allow airflow.
I have seen some in my opinion very dangerous things done also, ( I am a dealer trained Technician, And master ASE certified for 20+ years) I have seen drums actually drilled though the braking surface for ventilation( good concept but I would worry about the metalurgical structure after many heating and cooling cycles)
This link has some good info except for the idea of drilling the drums as I stated abovehttp://wps.com/AMC/1963-Rambler-American/Drums/

Here is a picture of a ventilated racing drum brake assemblies and othershttp://www.automedia.com/How_to_keep...es20051101db/1

Personally I would convert to discs, they are much more efficient.

Spence

[Deathvalleydog]

Originally Posted by Rooster's 67

We used front end components off of a 77 R20 (suburban for those not in the know)

That sounds like a good way to go. Besides a 77, what year models of Suburbans will work? I assume I'll have to call around local wrecking yards to find one. Or is there a better source? I live in CA on the central coast.