Brakes: Disk vs Drum

[PlasticMastodon]

A little background. I have a 75 Cherokee with drums all around. I also have a 3500lbs camper trailer. Nothing crazy. I plan to tow the camper with the Cherokee.

I was looking through and discovered that disk brakes seemed to be an option for the Cherokees. My question would be should I consider swapping the front drums out with disks? I know that is a lot of work, but would it be worth it? Are there bolt on options for this? I've never done anything like that, so I'm not sure.

Thanks,

[BCRAWLER]

Pretty sure to swap front to disc parts stores have most of the parts to do. Remember you also have to swap master cylinder and maybe proporioning valve.

[Stuka]

You definitely do NOT want to tow with the 4 wheel drums. My old Cherokee had drums all around, I towed with it exactly once, and then never ever again.

As for the conversion, its actually easiest to find another axle. But if thats not an option, you need the whole knuckle assembly, and the stub shafts are a different length as I recall.

But the braking difference is gigantic. Also, if you have non power drums, you really want to switch to power at the same time.

[PlasticMastodon]

Thanks.

Would it be crazy just to convert all 4 to disk?

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[Cecil14]

I'm running four wheel discs, and I never have any intention of going back. I am also running hydroboost, and the difference really is indescribable.

Rear discs are not difficult, but there are some things to watch out for. If you're six lug, there are plenty of off-the-shelf kits available. Not sure what the options are for five lug rigs.

[derf]

Thanks.

Would it be crazy just to convert all 4 to disk?

Sent from my Pixel 2 using Tapatalk

Not at all crazy to do that. I've done it on a couple of Jeeps. But I've also kept rear drums on several Jeeps as well.

The front disc conversion is the most important. Parts are available but as was said above, a donor axle swap would make it a lot easier. Though a worn out donor axle would provide the knuckle, spindle, shafts, and hub letting you rebuild the rotor, caliper, ball joints, bearings, and seals. You would end up with basically a "new" axle that way.

The rear disc conversion typically doesn't have a vast improvement in braking performance. Most of the braking is done by the front brakes. Simply rebuilding the rear drums with fresh, clean parts and getting it properly adjusted would probably be "enough". While discs all around are pretty much standard on most vehicles now, front disc/rear drum configurations were used for many decades without too many problems. I like discs because they're self adjusting and more resistant to fade as they heat up. But I like drums because they're easy and cheap to refresh.

While front discs are just swapping factory parts, a rear conversion requires that you build or buy a custom kit. And those kits can get expensive fast. You also have to figure out what to do about the parking brake. Some kits have it built in, some don't.

What it comes down to is how much you want to spend on your brakes. If you have a good budget, discs all around is a great option and a straightforward operation. If your budget is limited, keeping the rear drums is an attractive option.

[PlasticMastodon]

Thanks.

Would it be crazy just to convert all 4 to disk?

Sent from my Pixel 2 using Tapatalk

Not at all crazy to do that. I've done it on a couple of Jeeps. But I've also kept rear drums on several Jeeps as well.

The front disc conversion is the most important. Parts are available but as was said above, a donor axle swap would make it a lot easier. Though a worn out donor axle would provide the knuckle, spindle, shafts, and hub letting you rebuild the rotor, caliper, ball joints, bearings, and seals. You would end up with basically a "new" axle that way.

The rear disc conversion typically doesn't have a vast improvement in braking performance. Most of the braking is done by the front brakes. Simply rebuilding the rear drums with fresh, clean parts and getting it properly adjusted would probably be "enough". While discs all around are pretty much standard on most vehicles now, front disc/rear drum configurations were used for many decades without too many problems. I like discs because they're self adjusting and more resistant to fade as they heat up. But I like drums because they're easy and cheap to refresh.

While front discs are just swapping factory parts, a rear conversion requires that you build or buy a custom kit. And those kits can get expensive fast. You also have to figure out what to do about the parking brake. Some kits have it built in, some don't.

What it comes down to is how much you want to spend on your brakes. If you have a good budget, discs all around is a great option and a straightforward operation. If your budget is limited, keeping the rear drums is an attractive option.

Sounds like disc all around is the perfect setup, but front disc and rear drum is the more economical. Since I have many other things to fix, I think I will just stick with swapping out the front.

From what I can tell from looking around, I have basically two options for converting to disc in the front:
1. Drum to disc kit. This seems like it is a matter of pulling off the drum, putting on an adapter (sort of), then all the plumbing. I wouldn't have to drop the axle or anything. Has anyone done this? Does it work well?
2. Axle swap. This would basically give me a whole new axle. If I'm not mistaken, some of the newer (1980's) Wagoneers had front disc and they were narrow. Would one of those axles work?

[derf]

Sounds like disc all around is the perfect setup, but front disc and rear drum is the more economical. Since I have many other things to fix, I think I will just stick with swapping out the front.

From what I can tell from looking around, I have basically two options for converting to disc in the front:
1. Drum to disc kit. This seems like it is a matter of pulling off the drum, putting on an adapter (sort of), then all the plumbing. I wouldn't have to drop the axle or anything. Has anyone done this? Does it work well?
2. Axle swap. This would basically give me a whole new axle. If I'm not mistaken, some of the newer (1980's) Wagoneers had front disc and they were narrow. Would one of those axles work?

I do believe that all FSJ front axles went to standard disc brakes starting in 1976. And the knuckle/spindle/hub/brake setup is pretty much interchangeable from 76-91. And the outer stub shaft from any donor should work as well. Any donor axle can give you the parts you need. Any 1976-1979 donor narrow track axle will bolt right in (though you should make sure the gear ratios match). The 1980-1991 moved the differential to the other side so they would be a good source for parts.

[Stuka]

From what I can tell from looking around, I have basically two options for converting to disc in the front:
1. Drum to disc kit. This seems like it is a matter of pulling off the drum, putting on an adapter (sort of), then all the plumbing. I wouldn't have to drop the axle or anything. Has anyone done this? Does it work well?
2. Axle swap. This would basically give me a whole new axle. If I'm not mistaken, some of the newer (1980's) Wagoneers had front disc and they were narrow. Would one of those axles work?

You cannot use an 80's axle. They are driver drop, your axle is passenger drop.

You need an axle from a 76-79 Wagoneer or narrow track cherokee (not a wide track if swapping the whole axle). Although a wide track will work if you just needs the parts.

But, just to be clear. There is no 'kit' for this swap. You need to gather the parts yourself.

[tgreese]

The first year for optional disk brakes was 1974 for these Jeeps. 1976 may have been the first year for standard disk brakes - I'd have to check the book. (Later - Parts book says front drums were available through 1976.) As I understand the above, you cannot use the otherwise identical wide track Cherokee axle because you need the axle shafts from the proper width axle. Similarly, you cannot use the '80-up narrow track axle as a donor because the switch to driver's drop makes the length of the axle shafts different from the earlier passenger-side drop axles (is this correct?)

However, I suspect that the outer stubs are compatible, and if you are willing to take the axle shafts apart and swap the outer shafts from one of these other axles to your inner shafts, you'll have all the parts you need. If you can find a narrow track '74-79 disk brake axle with the right ratio, you could swap the whole axle, but I think you could also look for an axle that supplies just the knuckles, brakes and outer stub axles, and put the axle you need together from the parts. No experience with this, but that's what I would expect.

I would expect the pedal linkage, booster, master cylinder, combination valve and brake lines to be different too.

[tgreese]

I'd also comment that, due to weight transfer, most of the braking is done by the front wheels. You'll get a lot more benefit from the front disk conversion than converting the rear, ie it won't double the improvement. And there are no factory parts for rear disks, just aftermarket kits. An emergency brake is a lot easier with rear drums than disks - something to consider.

[MReese Wagoneer]

so my opinion
Disk Drum vs Disk Disk
for the Disk Drum conversion you need new Master Cylinder
For Disk Disk you need a different Master Cylinder Correct me if wrong

both you need to replace proportioning valve/diverter block

Is it worth extra to the Disk Disk first time around?????
money is always an issue but your tearing it apart for a front conversion is the time and effort worth the second round of work ?

[tgreese]

My opinion, never having done either conversion

Most of the stopping is done by the front tires, regardless of the brakes type. Your biggest benefit will be putting disks on the front, since they are self-wiping (work when wet - unlike drums) and do not fade like drums. Disk brakes are also easier to service than drums, and have a longer service interval than drums. The factory put disks on the front axles of these Jeeps, so adding them can be done with mostly junkyard parts. Any rear disk installation will require some kind of custom caliper bracket.

IMO the main advantage of drums on the rear is the parking brake - besides that they are already there, and that they don't contribute much to braking force, only to control. You can get calipers with a built-in parking brake (El Dorado calipers, maybe Wilwood?) but I read stories about issues with the Cadillac parts.

I'm an old hand at servicing drum brakes. It's not an obstacle to me. Many younger readers have never worked on drum brakes, and find them puzzling and frustrating.