Brake swap to disc

[Gator70]

I have been searching here for a while, and have seen lots of guys talk about putting disc brake on 2 wheel drives. What about 4X .Am i just overlooking the obvious. Is it easy enough to just get a newer D44 front axle and change the brake components. Is there issues with the steering arm. do you need a axle rotor to rotor or are some of the parts interchangable??
Help, lost in the brake zone
G

[chipotledude05]

I did basically the same thing with my '61. Even though I had a dana 44 in the front, the knuckles were closed and could only support drums. Also the pinion was questionable, but I digress. I bought a matching pair of 10 bolts from a late model suburban (i know i know, you'd think the 10 bolts are weaker, but in actuality, the carrier in the 10 bolt is larger and stronger than the d44). It's my understanding, however, that d44's with open knuckles have disc brakes, and that any 44 with the same characteristics will share parts, and there are a few parts that are interchangible even between closed and open knuckle axles. I believe the knuckle switch occured in '71, but I'm not for sure. Someone will be sure to come by who knows though. I also don't know about the part interchangibility between 10 bolt and d44.

Hope this helps,
Matt

[1969 GMC]

going by your username, I am guessing you have a '70?
if so, it is an oddball year for the front axle. It is the only year that GM offered open knuckles and drum brakes. brake drums are almost nonexistent for this application (just ask Jims70GMC, I am sure he will chime in).
the good news is, you can convert this axle over to disc brakes by using later model outer knuckles. I believe the steering arm is the same as the later model axles as well. or, if your axle is in bad shape, you could toss another axle under there to get discs.

[Budweis]

if indeed you have a 70 with open knucles well i just went through this on a 70. the drums are definitely non existant for new ones and i searched for 5 years and only found 1 turnable used one. the good news is you can just pull the hubs and backing plates and knuckles off a 71-72 and swap right on. im not 100% sure but it looks to me like you could use existing knuckles if drilled one hole on each side and tapped for the dust shield as the flat spot for the hole is already there and when i compared knuckes and measured thats the only difference i could see. i had a whole 72 differential so i just swapped from the knucles out. heres a few pics.

[poff]

I did my '70 K-20. It was all bolt on. If you can find them, some of the late 70's to early 80's caliper brackets were 360 degree instead of a bracket with a thin dust shield, these just bolt right up. The outer axle shafts are a little longer on the disc axles but I have heard a lot of people using the drum ones without the snap ring. The prop valve is available new or on any disc Chevy up to '72. I have heard of people using the later 5 connection prop valve and plugging one hole but I do not have any experience with this way. After-market, steel braided, brake hoses are the same price as stock ones and come in different lengths. Some people use the stock brake lines but it is easier to buy '71-'72 lines, if you call In-line tube you can order just the front lines (you may have to cut or lengthen the line that goes to the rear brakes though). If you go with new lines make sure you get the master to prop lines, they are hard to make. Disc booster, master, calipers and rotors are readily available, they are more or less the same from '71 to '87 if not later. The booster brackets are different for power drums then the power discs although I have heard of people using the drum ones. I have a set I got at the junk yard for $20, I'll sell them to you for $20 plus shipping. The best way is to find a donor axle and pull everything outside of the knuckle. You get everything you need off of a 10 bolt or D44. I tried to make this post short, reply if you have more questions. You can actually buy almost everything new from Spicer but it is expensive.

[Gator70]

Thanks for the tips guys. Budweis, I noticed that you swaped a 3/4 ton Im working with a 1/2 ton. Should be the same principles?? Sorry for the uninformed question but I have heard of open/closed knuckles. What does that actually mean. So it would appear that I pop the ball joints and replace from that point out. backing plate comes with caliper mount, spindle bolts to backing plate. is it the backing plate that also mounts the ball joints.

They say that there are dumb questions, but this is still a little new to me. Im a fairly decent replacemnt artist, but if it doesnt look exactly the same im sometimes lost.

I think that the axle in the front is a 44. that seems to be the popular axle. it wouldnt be something GM goofy I saw the tag fro the front didnt pay much attn to it other than 3.07 ratio.

[Budweis]

if you got ball joints you got an open like below. as far as if 3/4 ton and 1/2 ton the same im not sure hopefully someone will chime in.i would think it would still just be knuckles out job. poff is prob right bout the axle length and c-clip so id just grab the axles too. i used the axles out of the newer one but thought they were the same. i paid like 145.00 for the spicer kit with new axle u joints and all new hardware and bushings. then youll prob want to get new wheel bearings and races as well which werent cheap, least would be a good idea. if you replace all 4 ball joints your looking at about 120.00-140.00 for them, spindle bolts to knuckle with backing plate on same bolts. ball joints mount to knuckles. good news is rotors were cheap at autozone for like 29.00 each and like 39.00 each for calipers.

[poff]

At the axle 1/2 ton and 3/4 ton are the same. 3/4 tons just have larger diameter rotors, different caliper brackets (to accomodate larger rotors) and 8 lug hubs. The locking hubs are the same on '71-up but different '70-earlier. The booster brackets are the same but the booster and master are different. 3/4 tons have an extra bracket to support the booster because it sticks out so far.

[Gator70]

thanks for the tips guys, at least I know what to grab and what should fit. nothing worse than getting almost ready to button it up and something goofy wont fit. like the steering arm or such. these trucks arent that plentiful around this part of the world, so ill have to make this a search and wait type mission. this gives me a good place to start though.

[JIMs70GMC]

The steering arms are the same for the 70 and 71 and up trucks. Held on w/ 3 studs/nuts. I paid $50 each for my used drums($60 shipping from CA) and when they are gone I'll go discs myself. If you can find an axle from a 71 to 87 GM truck and your in business, the biggest thing that changed is the GM 10 bolt front uses a metric banjo fitting on the caliper. The hard to flexible brake line fitting at the frame is the same.

[Gator70]

thanks Jim

[poff]

I am not sure of the exact year but if you can find a later axle it should have heavier duty inner axle shafts than the early '70s. This is only helpful if you find a D44. You can tell because your stock ones (If they are original) will taper up to the splines. The later heavy duty axles are a lot thicker and taper down to the splines. These are direct replacements.

[6869704X4]

Try and and find a 73+ Dana44. Its a bolt in. Master cyl for a disc/drum. I wound up using a adjustable prop valve. Earls got the lines to get to the caliper

[BurnoutNova]

gator70:

i have a pair of disc brake axles in fine shape, from a 73 blazer

let me know if you need them

[Gator70]

thanks nova, im going on the hunt for pieces. this will be a good winter project. that is if the wife lets me take over her half of the garage. I spotted a rusted out ole p/u in a farmers back yard. bunch of stuff already taken.

Do I need to change the brake booster as well or just the m/c.etc....

[BurnoutNova]

i dont think you need to change it... but i havnt ever swapped discs for drums... so i dont know!

if i end up parting the disc parts off this axle i'll let you know


zach

[BurnoutNova]

1969 GMC :

is that what i think it is in you avatar?

LOL

[1969 GMC]

Originally Posted by BurnoutNova

1969 GMC :

is that what i think it is in you avatar?

LOL

[BurnoutNova]

Originally Posted by 1969 GMC

i thought so lol

[JIMs70GMC]

As far as MC/booster, I swapped a 70 cab (2wd w/ 4 drums) on to a 71 chassis(disc/drums) and did not change anything, hooked the brake lines up and have had no problems stopping. Will lock the rear drums up with nothing in the bed, but has no problem stopping.