What do I need to go back to drum brakes in the rear?

[PatrickRyan]

PO installed a kit from SSBC to have disk brakes in the rear of my '78 CJ5 .

Fast forward to this past weekend. Easter Sunday, of course...
Brakes are kind of mushy. I can pump them a couple of times and build up pressure. I figured I had some air in the lines.

I go to bleed the brakes. Get to the left rear and no luck. The bleeder valve is way more than hand tight. So, I spray some penetrating oil on it and go eat dinner with my family.

I come back several hours later and crawl back under the jeep. Still way too tight. Sure enough, I torqued it off.

SSBC guys this AM saying that they doubt if I can EZ out it and get it to seal. I need a new caliper. Couple hundred bucks, at least. Depends on the model, which I don't know. So I need to send them a picture of the unit when I get off work.

So, I got to thinking, why fix Frankenstein's jeep? What about returning to stock?

What all do I need to revert it back to drums?

I'm going to call Vintage Jeep this morning, as soon as they open.

 

[cglax6]

Although I'm no fan of SSBC's kit, I would recommend keeping it vice going back to drum brakes.

Here's why...please bear with me...

I have a 76 CJ5 and it came with a plethora of PO issues...one being that there was just something wrong with the brake system. First, I replaced the front drums with discs with a kit from Horsepower, LLC. It was a great no-fuss bolt-on solution that required no grinding like all the other kits. Seeing as I didn't replace the rear drums, I had to get a new MC and prop valve designed for disc/drum brakes. I also replaced all brake lines and fittings while I was at it. After driving for a while, the brakes were still a little wonky and I was able to isolate some vibration coming from the rear axle. I replaced all drum components...wheel cylinders, springs, shoes, drums, etc...and made adjustments. Still had issues and just couldn't get rid of the vibration. I took the rear brakes apart again and could tell that they were dragging and vibrating as evidenced by the perpendicular lines on the inside of the drums. Seeing as I just replaced everything, I decided to replace the rear brakes with a kit from TSM. The kit was similar to the SSBC kit, and didn't come with the best instructions, but the folks at TSM...mom and pop shop...walked me through a few questions that I had, and got everything on perfectly. Seeing as I put discs in the back, I had to install another new MC and prop valve (and new dual diaphragm booster just because) made for a disc/disc brake system.

After bleeding the lines and making the correct adjustments, my ride is a smooth as can be and I don't get any more vibration from the brake system. To this day, I still can't figure out what the issue was, but it worked out.

Here's what you have to think about when you move back from discs to drum in the rear...

-New MC for the new brake configuration ($$)
-New PV for the new brake configuration ($$)
-You'll have to pull the axles to get the caliper mounts off and drum backing plate on. When you pull the axles, you'll want to replace the seals. To replace the seals, you'll need to pull the bearings and press new ones on. ($$)
-You'll have to get everything you need for fresh new drum brakes for both sides ($$)
-You will never find a drum that is perfectly round (or with a hub that is centered), and you'll get some annoying brake squeak. I returned 8 rear drums because of how bad they were when doing my rear drum project.

By the time you're done with replacing your rear discs with drums, you will have reduced capability and spent about triple of what you would have if you just replaced the caliper.

I suggest finding out what caliper they use and order from someone else or pick from a lot somewhere. My rear calipers were from an 80-85 Eldorado and a bunch of others. SSBC didn't design a whole new caliper for their kit...they source it from another vehicle.

 

[PatrickRyan]

Although I'm no fan of SSBC's kit, I would recommend keeping it vice going back to drum brakes.

Here's why...please bear with me...

I have a 76 CJ5 and it came with a plethora of PO issues...one being that there was just something wrong with the brake system. First, I replaced the front drums with discs with a kit from Horsepower, LLC. It was a great no-fuss bolt-on solution that required no grinding like all the other kits. Seeing as I didn't replace the rear drums, I had to get a new MC and prop valve designed for disc/drum brakes. I also replaced all brake lines and fittings while I was at it. After driving for a while, the brakes were still a little wonky and I was able to isolate some vibration coming from the rear axle. I replaced all drum components...wheel cylinders, springs, shoes, drums, etc...and made adjustments. Still had issues and just couldn't get rid of the vibration. I took the rear brakes apart again and could tell that they were dragging and vibrating as evidenced by the perpendicular lines on the inside of the drums. Seeing as I just replaced everything, I decided to replace the rear brakes with a kit from TSM. The kit was similar to the SSBC kit, and didn't come with the best instructions, but the folks at TSM...mom and pop shop...walked me through a few questions that I had, and got everything on perfectly. Seeing as I put discs in the back, I had to install another new MC and prop valve (and new dual diaphragm booster just because) made for a disc/disc brake system.

After bleeding the lines and making the correct adjustments, my ride is a smooth as can be and I don't get any more vibration from the brake system. To this day, I still can't figure out what the issue was, but it worked out.

Here's what you have to think about when you move back from discs to drum in the rear...

-New MC for the new brake configuration ($$)
-New PV for the new brake configuration ($$)
-You'll have to pull the axles to get the caliper mounts off and drum backing plate on. When you pull the axles, you'll want to replace the seals. To replace the seals, you'll need to pull the bearings and press new ones on. ($$)
-You'll have to get everything you need for fresh new drum brakes for both sides ($$)
-You will never find a drum that is perfectly round (or with a hub that is centered), and you'll get some annoying brake squeak. I returned 8 rear drums because of how bad they were when doing my rear drum project.

By the time you're done with replacing your rear discs with drums, you will have reduced capability and spent about triple of what you would have if you just replaced the caliper.

I suggest finding out what caliper they use and order from someone else or pick from a lot somewhere. My rear calipers were from an 80-85 Eldorado and a bunch of others. SSBC didn't design a whole new caliper for their kit...they source it from another vehicle.

Yeah, wow. I didn't think about any of that. Plus, according to Russell at Vintage Jeep parts, nobody remade the backing plates. So, more money there sourcing original parts off ebay or cragslist or someplace.

Thanks
Patrick

 

[RiverandSand]

By the time you're done with replacing your rear discs with drums, you will have reduced capability and spent about triple of what you would have if you just replaced the caliper.

I suggest finding out what caliper they use and order from someone else or pick from a lot somewhere. My rear calipers were from an 80-85 Eldorado and a bunch of others. SSBC didn't design a whole new caliper for their kit...they source it from another vehicle.

This ^ no reason to go backwards. I would take the caliper to a brake shop they may be able to fix it or source a replacement.

 

[cglax6]

I would take the caliper to a brake shop they may be able to fix it or source a replacement.

I have a go-to machine shop to deal with things like this...call around town and see if anyone can help you out. I also made friends with a guy that runs a local restoration shop...either place would do stuff like this for free because I use them a lot for the bigger stuff.

Someone should be able to fish the threads out for you. If they can't, then work on getting a new caliper.

 

[PatrickRyan]

I have a go-to machine shop to deal with things like this...call around town and see if anyone can help you out. I also made friends with a guy that runs a local restoration shop...either place would do stuff like this for free because I use them a lot for the bigger stuff.

Someone should be able to fish the threads out for you. If they can't, then work on getting a new caliper.

I spoke with Chris at SS Brakes this morning. Turns out that the bleeder valve we broke is on what they call a Bendix Bolt. It's some kind of adapter that screws into the caliper. Not sure of its function honestly. Chris said it is necessary due to the SSBC kit having the caliper upside down. Anyway, it can be removed from the caliper and replaced. He's got 2 coming to me.

So, I'll maybe get ole yeller back on the road this week. We'll see.

 

[RiverandSand]

That's good news, hope once you get the bleeder fixed, you can bleed the system.

 

[cglax6]

I spoke with Chris at SS Brakes this morning. Turns out that the bleeder valve we broke is on what they call a Bendix Bolt. It's some kind of adapter that screws into the caliper. Not sure of its function honestly. Chris said it is necessary due to the SSBC kit having the caliper upside down. Anyway, it can be removed from the caliper and replaced. He's got 2 coming to me.

So, I'll maybe get ole yeller back on the road this week. We'll see.

Definitely good news.

Did you get him to divulge what caliper and rotor they use? It'll be good info to have for the future when you need new pads and rotors.

Also, when you bleed those brakes, make sure the bleeder screw is pointed upward and is the highest point...otherwise you won't be able to get all the air out.

My only gripe about the kit that I used from TSM...and it's only an issue because my axle was rotated about 15 degrees to address some driveline angle problems...is that the bleeder screws were not at the highest point and weren't pointed up, and I had to bleed the system with the calipers off their mounts. Not a big deal in the end, but if I hadn't done it that way, air would still be trapped in the caliper and I'd have some squishy brakes.

Let us know how it goes.

 

[PatrickRyan]

Definitely good news.

Did you get him to divulge what caliper and rotor they use? It'll be good info to have for the future when you need new pads and rotors.

Also, when you bleed those brakes, make sure the bleeder screw is pointed upward and is the highest point...otherwise you won't be able to get all the air out.

My only gripe about the kit that I used from TSM...and it's only an issue because my axle was rotated about 15 degrees to address some driveline angle problems...is that the bleeder screws were not at the highest point and weren't pointed up, and I had to bleed the system with the calipers off their mounts. Not a big deal in the end, but if I hadn't done it that way, air would still be trapped in the caliper and I'd have some squishy brakes.

Let us know how it goes.

I sent him an email about the rotors and calipers. We'll see what he says.

I thought he said they were from an 88 Thunderbird while I was talking to him, but I wasn't paying as much attention to that as I should have been.

Hopefully, he will respond pretty quickly.

I'm kinda concerned that I will need a new master cylinder. The one wheel that we did get to bleed (the right rear) didn't really get a lot of fluid flowing out. And the pedal never really pressured up.

 

[cglax6]

I'm kinda concerned that I will need a new master cylinder. The one wheel that we did get to bleed (the right rear) didn't really get a lot of fluid flowing out. And the pedal never really pressured up.

What was your procedure for bleeding? There's a few different ways to do it...some better than others.

Very rarely will you need a new MC.

This is the process I use, and I've never had a problem:

-Engine can be running or not. I have it running because the wife or kids press the brake for me and it makes it easier.

-Attach bleeder bottle to brake with longest line (usually rear passenger). Get the wrench ready.

-Have your partner slowly press the brake pedal, as they press down, crack open the bleeder valve until fluid starts coming out.

-When your partner gets to the bottom of their stroke, have them hold it down. While they hold it down, close the bleeder valve.

-When the bleeder valve is closed, your partner can let go of the brake.

-Repeat this process until you don't see any more bubbles come out.

-Don't let the MC run out of fluid, or you'll have to bench bleed the MC and bleed the whole system again.

-Repeat for all brakes until there is no more air in the lines.

-If you're certain you don't have any more air in the lines and the brake pedal is still squishy, then you may have air in the MC and you'll need to bench bleed it. After bench bleeding, you'll have to bleed all 4 brakes again.

When I bleed brakes, I make sure I pump enough fluid to get all the old fluid out of the lines...and then some.

Make sure your partner presses the brake pedal slowly...if you have air in the line and they press it too fast, it'll turn big bubbles into smaller ones...makes it more of a pain.

Don't waste your money on one of those vacuum kits that they sell at the part stores...they're junk.

 

[PatrickRyan]

What was your procedure for bleeding? There's a few different ways to do it...some better than others.

Very rarely will you need a new MC.

This is the process I use, and I've never had a problem:

-Engine can be running or not. I have it running because the wife or kids press the brake for me and it makes it easier.

-Attach bleeder bottle to brake with longest line (usually rear passenger). Get the wrench ready.

-Have your partner slowly press the brake pedal, as they press down, crack open the bleeder valve until fluid starts coming out.

-When your partner gets to the bottom of their stroke, have them hold it down. While they hold it down, close the bleeder valve.

-When the bleeder valve is closed, your partner can let go of the brake.

-Repeat this process until you don't see any more bubbles come out.

-Don't let the MC run out of fluid, or you'll have to bench bleed the MC and bleed the whole system again.

-Repeat for all brakes until there is no more air in the lines.

-If you're certain you don't have any more air in the lines and the brake pedal is still squishy, then you may have air in the MC and you'll need to bench bleed it. After bench bleeding, you'll have to bleed all 4 brakes again.

When I bleed brakes, I make sure I pump enough fluid to get all the old fluid out of the lines...and then some.

Make sure your partner presses the brake pedal slowly...if you have air in the line and they press it too fast, it'll turn big bubbles into smaller ones...makes it more of a pain.

Don't waste your money on one of those vacuum kits that they sell at the part stores...they're junk.

That's pretty much the process I was using. However, the petal will never pressure up. It's loose almost all the way to the floor. Very little fluid comes out. And fluid level in MC doesn't move at all.

At least before I started the process, when driving, I was able to pump the pedal and get some pressure on it. After trying to bleed the right rear, no more pressure, even after pumping the pedal several times.

No idea what I'm doing, but followed the steps you listed.

 

[cglax6]

After trying to bleed the right rear, no more pressure, even after pumping the pedal several times.

Is this with the engine running? When you say no pressure, does the pedal fall to the floor on its own? Hopefully, you just mean "little pressure."

When you have a soft pedal like that, it means there's air in the system, and that air is being compressed, instead of one solid column of fluid being pushed.

When the engine is running (assuming you have a vacuum booster), you're getting an assist from the booster which makes it feel like it's easy to push. This effect will be amplified (a lot) if there is air in the system.

If the pedal falls to the floor on its own, you have a catastrophic failure somewhere and you'll see fluid coming out of your MC. Even if you had a massive hole in a brake line, you'd still have to press the pedal down...and fluid would come out of that hole in your line.

Sounds like you have a lot of air in your lines. Just need to keep at it. The whole system has to be closed to do this right. You're not going to get a hard pedal until all of that air is out.

If there's air in your MC, you'll never get a hard pedal. You may want to think about bench bleeding your MC. You can do it in place. Follow the same steps as with bleeding the lines, but instead of opening and closing the bleeder valves on the brakes, you'll have to crack open and close the 2 brake line fittings (bleed one at a time) on the side of the MC. There's no way to catch the fluid coming out, so you'll need a big towel or a lot of rags. Do your best to keep the fluid off all your surfaces...brake fluid is some nasty, corrosive stuff, and will melt right through a nice paint job if left unchecked. After you bleed the MC, you'll have to bleed the brakes again.

I doubt there's air in your MC though, since you say you had a hard pedal before doing all of this...unless you let a reservoir dry up...then you'll get air in your MC. When you get your caliper fixed up, do it all again, and keep at it.

Soft pedal=air in lines/MC or fluid leak

 

[PatrickRyan]

Is this with the engine running? When you say no pressure, does the pedal fall to the floor on its own? Hopefully, you just mean "little pressure."

When you have a soft pedal like that, it means there's air in the system, and that air is being compressed, instead of one solid column of fluid being pushed.

When the engine is running (assuming you have a vacuum booster), you're getting an assist from the booster which makes it feel like it's easy to push. This effect will be amplified (a lot) if there is air in the system.

If the pedal falls to the floor on its own, you have a catastrophic failure somewhere and you'll see fluid coming out of your MC. Even if you had a massive hole in a brake line, you'd still have to press the pedal down...and fluid would come out of that hole in your line.

Sounds like you have a lot of air in your lines. Just need to keep at it. The whole system has to be closed to do this right. You're not going to get a hard pedal until all of that air is out.

If there's air in your MC, you'll never get a hard pedal. You may want to think about bench bleeding your MC. You can do it in place. Follow the same steps as with bleeding the lines, but instead of opening and closing the bleeder valves on the brakes, you'll have to crack open and close the 2 brake line fittings (bleed one at a time) on the side of the MC. There's no way to catch the fluid coming out, so you'll need a big towel or a lot of rags. Do your best to keep the fluid off all your surfaces...brake fluid is some nasty, corrosive stuff, and will melt right through a nice paint job if left unchecked. After you bleed the MC, you'll have to bleed the brakes again.

I doubt there's air in your MC though, since you say you had a hard pedal before doing all of this...unless you let a reservoir dry up...then you'll get air in your MC. When you get your caliper fixed up, do it all again, and keep at it.

Soft pedal=air in lines/MC or fluid leak

I'll do that. As soon as the parts come in, I'll try again. Thanks for all the help.

Patrick

 

[PatrickRyan]

The part they are sending is a Banjo Bolt. I don't know where I go the Bendix Bolt from. Thinking starter lol

The caliper is off an 88-91 Thunderbird Turbo Coupe.
FMSI# D-347

Chris says I would need to get replacement rotors through them. +- $80 I think from what I saw on their web site. I need to get the exact model number off the unit under my Jeep to be sure which of their rotors it is. He told me where to look to get the number. I should have that info this evening.

I am ready for my mid-life crisis mobile to be back on the road lol.

It was either this or 77 Corvette.

 

[cglax6]

The banjo bolt is what keeps the brake line on the caliper and it allows fluid to pass through it and the banjo fitting.

Now I'm confused as to why you shredded that bolt trying to bleed the system.

First photo is the banjo fitting securing the brake line to the caliper. Second photo is the bleeder screw that you connect your bleeder bottle hose to when you bleed the brakes.

Sent via Google translate using braille through Tapatalk

 

[PatrickRyan]

The rear disk brake kit from SSBC uses a hollow banjo bolt with the bleeder valve threaded into it. They tell me it is because their caliper is upside down. I believe this banjo bolt is of their own design.

If you drilled a hole into the head of that bolt you pictured, all the way through and then threaded a bleeder valve into the hole, you would have what I have.

Trust me, it doesn't make much sense to me either. But the parts are here today, and hopefully, I can get her back up and running.

Patrick

 

[RiverandSand]

If you drilled a hole into the head of that bolt you pictured, all the way through and then threaded a bleeder valve into the hole, you would have what I have.

Trust me, it doesn't make much sense to me either. But the parts are here today, and hopefully, I can get her back up and running.

Patrick

Well it sounds like SSBC it trying to get to the highest point, however it will still be hard to fill the caliper with fluid since you don't have two separate points for the fluid to flow to. Might try to prefill the calipers first (like a master cylinder bench bleed) but no pumping, then let them sit abit for air to work out. I would also look into pressure bleeding the system. HF has pressure bleeding kit for about 30 bucks. I used it on mine and it worked good.

 

[PatrickRyan]

Well it sounds like SSBC it trying to get to the highest point, however it will still be hard to fill the caliper with fluid since you don't have two separate points for the fluid to flow to. Might try to prefill the calipers first (like a master cylinder bench bleed) but no pumping, then let them sit abit for air to work out. I would also look into pressure bleeding the system. HF has pressure bleeding kit for about 30 bucks. I used it on mine and it worked good.

I looked at that kit. Almost bought it. Might go that route if I continue to have problems.

Got the new banjo bolts installed. I figured that since 1 was jacked up, might as well replace both. I finally got everything bled. Enough to get working brakes, at least. Much better than it was. As Willie would say "On the road again..."

Thanks for all the help guys.

 

[cglax6]

I guess it's just cheaper for them to drill and tap some bolts than it is to design a bracket that would keep the bleeder screw up high.

I had a similar issue on my rear brake kit from TSM. My rear axle is rotated about 17 degrees to accomodate a lift and double cardan drive shaft. Because of that, the bleeder screw wasn't at the highest point. Easy fix...unbolt the caliper from the bracket and rotate it when you bleed it...bolt it back in and all set.