I think I got the wrong axle for the D30 disk brake swap

I bought a dana 30 out of a 78 CJ from one of the guys in my Jeep club to get the brackets from so I could do the conversion.

I got it a few months ago and hyave been working on other things. It is rusty so I didn't look it over real close until today when I started putting PB on it for this weekend.

I am not sure, really, but I don't think this is the axle I need to convert my 75. The rotors should be 1 1/8 but they measure just a tiny bit below an inch.

Where do I count the bolts at? It has two big bolts holding the caliper to the bracket. It looks like it has 6 bolts holding the bracket to the axle.

I looked HERE to try to identify the date the axle was made but there is nothing where the chart shows I should have a date. In fact, all I have is the ratio tag.

The ratio tag says:
5362979
3 54 46-13

Does 5362979 mean anything? Like that it was made in June of 79?

If the axle is the wrong one, can I just use the knuckles and caliper bracket (clean up the rust), get new rotors, calipers, pads and hardware kits and still go to disks?



Also, I read this on www.off-road.com and it sounds real promising for me, but it isn't interactive and full of proven knowledge like you guys

CJ Dana 30s
Early Dana 30s used a 11"x2" drum brake. Disk brakes were optional in 1976 and standard starting in 1977. Between '76-'78 the disk brakes used a large 10-1/2"x1-1/8" rotor. The "big brake" setup uses a 6 bolt caliper mounting bracket that goes between the knuckle and the spindle. The caliper is keyed to the mouting bracket and the rotor should apear wide when looking on edge. Rubber brake hoses with brass banjo fitting end. These rotors, calipers, and pads are compatible with the Scout II.

From 1979-1986 they used a 10-1/2"x7/8" rotor with a 2 bolt to knuckle caliper mounting bracket. From '79-'81 the caliper is keyed to the mounting bracket and uses rubber brake hoses with brass banjo fitting end. From '82-'86 the caliper is pin-bolted to the caliper bracket and the hoses are rubber crimped to steel line.

All Dana 30s from 1972-1980 use a six bolt locking hub. From '72-'78 the factory had Warn Premium hubs as an option. From '79-'80 the factory used Warn non-premium hubs stock. From 1981-1986 they use a weak Warn five bolt locking hub stock. Jeeps built in the 70s with the Quadratrac transfer case will not have hubs at all unless they have been converted to part-time operation. They have driven plates instead. Hubs should not be used with this transfer case unless it has been converted to part-time operation.

Another big difference between the CJ and Dana 30s used in later models is the CJ has the diff case offset on the passenger side and the later models have the diff case offset on the drivers side.

Most CJ Dana 30s will have lock-outs on the hubs to engage or disengage the wheel from the axle. With both hubs unlocked, the axles, u-joints, differential, and front drive shaft do not spin. This is done to increase gas milage, and if a locker is installed in the front diff, it will impove handling on the pavement. Later model Dana 30s either an axle disconnect system or no disconnect system.

The CJ Dana 30 uses the 5 on 5.5" wheel bolt pattern other models use the 5 on 4.5" wheel bolt pattern.

Outer parts (knuckles out) can be switched amoung to different versions of the CJ Dana 30. This means CJs with drum brakes can upgrade to disk and CJs with cheesy 5 bolt locking hubs can upgrade to 6 bolt locking hubs. Later models use different knuckles and ball joints that are not compatible to the CJ Dana 30.

Common gear ratios from '72-'75 were 3.73, from '76-'79 were 3.54, and from '80-'86 were 2.73

 

That won't bother me one bit. I just need to get a working disk brake setup on the front to work out the last of the bugs.

When you say the whole ball of wax, do I need to swap out the axle shafts and and out, the knuckles and out, or just the caliper bracket out?

 

the axle tag given comes up 1981 and later CJ, 3:54 ratio
has it been changed/modifed by the club member, who knows.
which means it may have (originally) the 2 bolt caliper mounting bracket pictured below.
I'm not the expert, but it seems you want the 6 bolt version also shown below.
the number of bolts refers to where the bracket bolts to the knuckle.
I think you would have to swap knuckles and all in order to
make it work.
others here will know more than I on this subject...

 

the axle shafts for 1981 and prior are narrow track and should be the same length, no worries there.

I type too slow........

 

Have I mentioned that I love you guys? After all the problems I have had with this beast, it is nice to get not only good news but useful news, too

Thanks, guys!

 

When "The Oracle" came over to look at my alternator wiring issue an offer suggestions, he pointed out that before I worry about doing th edisk conversion, i need to adjust all 4 drums. He didn't know I had 11 inch drums.

 

Nah

What he was thinking was that I had smaller drums and he figured that since I was going to do disks anyway, I would be better off doing that and then worrying about the mooshy pedal if it was still a problem.

He said that since I have 11 inch drums, I should try adjusting them first to see if that takes care of the pedal.

I don't suppose a 1975 CJ-5 has self adjusting drums? I'll drive around the block in reverse 30 times

 

the '75's did have self-adjusters, but by now, they may not be in operable condition.

in all seriousness, take the drum off and look at the brake mechanicals. they aren't too terrible to learn how they work. i started from zero when i bought my '75, and over the last 11 years, i now have no problem with pulling everything and readjusting where necessary. having brake tools will make the job a little easier than just using pliers/screwdriver/etc.

i also have the knuckles/outers to swap in discs for my front drums. just haven't gotten a round tuit.

wally

 

U.S. cars all had self-adjusting drum brakes by 1960 or so ... and many had front disks a few years later. Except for electronics stuff and changes in materials, cars have not changed that much over the past 50 years. Peoples's tastes and government requirements have changed, but the technology is quite mature.

The 11" drums should be ok - disks replaced drums mostly becasue the service interval on disks is longer, and drums are not self-wiping like disks. JMO - the disks are a worthwhile upgrade, but they aren't a huge improvement like on earlier Jeeps (ie those with 9" or 10" drums).

 

It sounds good to me. Tomorrow, I should know if adjusting the brakes does the trick or not. I'm and my steering shaft is coming in. I might actually get the day off work, too. I'd love to drive that durned thing to the car show... the Jeep club I am in gets together there every other Friday night.

 

I did the swap out with the same style of caliper mounts (2 bolt) on my 72. I had no problems I just unbolted the knuckles and swapped them complete. The only trouble I had was with bleeding the air out of the system the way the calipers mount there is an air pocket in them. You need to gravity bleed them with the bleeder straight up to get the air out.

 

Thanks for the information, Beav! (Did you know I have a kitten named Beaver and I call her Beav all the time? small world! If I knew she knew so much about brakes.... errrr... wait... nevermind).

I have the axle sitting in a protected area waiting for my next cash infusion for the project.

I found out that Tiure Kingdom didn't inspect the brakes at all, so the shoes were worn down to metal. A buddy of mine helped me replace them (along with new drums) Friday but, overnight, one of the wheel cylinders popped, so, one day this week, he is coming back and we'll get the rear brakes and all 4 wheel cylinders, then bleed them out.

 

Common problem with tired wheel cylinders. Mine did not leak until I replaced the shoes front and rear, then all the wheel cylinders began to leak.

 

I'll have all new shoes, two new drums (maybe 4 if the back ones are bad), new cylinders, new MC (a much stronger one than originally) and a vacuum booster to top it all off. I am hoping that will stop the 35s ok and I don't have to worry about the disk conversion for a while.

 

I'm running 11" drums all the way around without power assist on top of 35s and it seems to stop okay. However, I rarely exceed 60mph.

 

Still run the original MC?

I put the MC and booster out of an 86 e350 in mine