The Stovebolt Site Forums The Shop Area Driveline Disc brake conversion

Okay so I decided to upgrade my brakes to disc. I ordered what I needed from Brothers. They sent the kit which looked ok. I followed the video and stumbled a little but all ok. When I tried to assemble the caliper with brake pads installed and they won’t fit the disc. I questioned my assembly of the hub etc. I could find nothing I did wrong. I then measured the width of the unassembled disc 31.5 mm (the other wheel) and space between the caliper pads-33.5 mm obviously the spacing is too narrow to fit the disc. Any ideas to make this right? Thanks.

Did you compress the piston on the caliper?

Well, 31.5 mm disc thickness is less than 33.5 mm space.....that there is a clearance fit Clarence. In the United States of America we use inches to measure things like that. That there is a clearance of .03937 per side. Perfect.
Robert: Can you re-do that question and in inches? Glad to help.

If you have transposed the numbers, my first reaction is the same as Phil's. Squeeze it more. You need to be careful not to squirt out of the reservoir while squeezing. Let us know.

Did you buy your own caliper and pads or did it all come with the kit????????????

Hi guys. Yes I did reverse the numbers. You get the idea. Having said that I guess there is a negative 2mm clearance. The entire set including pads was purchased from Brothers. The disc is too wide for the assembled pad and caliper.

Pictures might help ?

Is that all they give you for instructions? A video?

As mentioned above, you can compress the piston in the caliper using a c-clamp to provide the clearance you need.

Is this it: https://www.brotherstrucks.com/1947...SC-BRAKE-CONVERSION/productinfo/NOFX559/

Pictures enclosed

I elastics are to hold in pads place when assembling caliper on disc. Compressing them is not what I need. I need more space between pads to fit the caliper on disc. Pads are to thick?

From the one picture it appears the pad opposite the piston is not fully pushed outward. Looks like a gap between back of pad and caliper

No gap. Pads are flush to sides of the caliper.

I just spoke with Brothers. There trying to figure it out. The pads appear to be too thick.

If the piston is flush or below surface of caliper housing, you are correct. Either rotor is too thick or pads too think. Can't imagine them making a mistake after selling so many kits. It will boil down to their supplier (if it's not you)
You are using the correct approach, trying to fit the rotor into pads without mounting either. I assume all pads are the same thickness and not one thicker than the other.
I assume they will measure the pad thickness of another set and tell you the dimension for you to check yours. As you know the fit is going to be tight. That is normal for disc brakes.
We have all had this trouble when we replace pads. It's always been that piston needed more squeeze.

I’m anxious to see what Brothers tech says. I’ll keep you updated . They’ll get back to me on Monday. Thanks to all members for advice. I will try the c clamps tomorrow but I have my doubts.

I agree with bartamos. It only takes one millimeter to be too tight. Even though the pad looks like it’s flush with the caliper, it might need that extra one millimeter to get them to fit. A C-clamp guarantees that.

I managed to get the pads on with caliper. It was very tight. The only way they went on was to depress the caliper with a C Clamp. The only thing is the pads are so tight on the caliper that the disc itself won’t move- at all. I take it this is not normal? Any response is greatly appreciated.

Your right, that is not normal. Is the other side the same?

You said you stumbled a bit when you installed the kit. If the caliper or rotor is not in their correct positions, it could cause you not getting the pads on properly. I would relook at any literature, rewatch the youtube video and maybe it will strike you as to what is wrong.

If you can’t get any further, I would continue your contact with Brothers. Its their product and they want you to be a satisfied customer.

Yes both sides. I was thinking of taking a sanding block with a fine grit and taking down the pads a bit.

I would talk to Brothers first. If you sand the pads, you won’t be able to return them.

Are you doing disc in front and drum in rear or disc/disc??? What master cylinder part number did you order? What is the brake kit part number?

Agree^^^^^^^^^^^

Past reported errors on disk conversion:

Left right mounting brackets swapped. Most kits the brackets have a slight off set.
Calibers mounted upside down.
Bearing installed in the hub is wrong.
Spindle spacer is wrong or not seated.
Spacing on the rotor hat incorrect.

Hi Bartamos. Thanks for the advice. The conversion kit is assembled correctly. However, I don’t feel comfortable finishing the job if the disc does not turn. I don’t want to have to pull the wheels off again if the brakes don’t work right. But I’m wondering have you done this type of disc brake conversion before? It seems logical that discs can be tight but I should be able to turn the disc. Btw I have installed a proportioning valve and reconnected the lines correctly. This installation went pretty easy. Yes I do have a dual master cylinder which I removed and bench bled and reinstalled when I put in the proportioning valve.

I’m still waiting to hear fromBrothers. It seems they’re only a distributor if parts and are at the mercy of the manufacturer as what to do in this situation. They said did I compress the caliper. I did. They also asked if I tried removing the backplate. When I asked how to do that they didn’t know. When I asked if I could get the backplate off then what should I do? They didn’t know. So thus far they’ve been no help, The last I heard from them they told me to send them pics of the box the calipers and pads were shipped in.

I believe they want to make sure they sent you the right parts. Make sure you also show the labels in the pictures.

Have you installed the tire and wheel. Trying to turn the rotor may be really tight until everything gets seated. If your sure you have installed it correctly, I would follow Bartamos’s advice and try it. It might need some force to seat the pads.

I have installed a bunch of disk brake pads, you will not be able to install the caliper if the pads are tight enough to lock the rotor. Sand the face of each pad a bit, and make sure each pad seats correctly into the caliper. Bolt the tire and wheel on, if you still can't turn it, then you have something out of alignment.

Hank you. This makes completes sense

Don't sand anything. Don't modify anything. You will never get relief from vendor, if necessary.

1. Disc to pad spacing is very tight because there is no return spring like on shoes. The pressure is relaxed, that's all. IT'S NORMAL.
2. Rotor is a small diameter, not much leverage to overcome tight fit caused by things not settling in yet. When tire gets on, and you roll down the road, you will "loosen" the pads a hair more. As JoeH says. Jack up one wheel with tire on. Check spin. Let it down. Drive back and forth in driveway or down the road. Jack back up and check spin.
A normal new disc brake will have contact or near contact with rotor and pad. Contact is friction. Friction is resistance.
3. The fact you got it together proves you have the right parts. As JoeH says. Bench bleed may or may not be enough. May need system bleed also.
4. You say you can't get much help from vendor. You ignore the ENORMOUS help you are getting on Stovebolt. The vendor says "we don't know" this or that. We do know. What is your problem with taking our advice? What advice do you want?
5. Yes, we have much experience on here. Most of the responders have done a disc brake conversion or two. Most have replaced pads on a vehicle or two. Including me for both.
6. When a person asks for help, then does not answer questions and rejects the advice without any knowledge, as Jerry would say, I'm done.

I used a kit from Brother on my 59'. It was complete with all the hardware, instruction were a little vague as you say. They do have a DIY link on their page, it has the Disc Brake kit there... I was just wondering if you seated the caliper bracket correctly, the pads should have some drag but not to the point that they won't turn... Have you measured the rotor with a micrometer and checked that measurement against the gap between the pads, that would be a starting point.

Where do I start to answer Bartamos? First I’m grateful for all suggestions from members, even those that may or may not know what there talking about. I did sand just a bit the pads and this did the trick. Discs move with some drag. Of course I will bleed the entire system, it’s routine.. I’m not sure why you seem upset but keep the blood pressure down - if this forum upsets you then you should be done. It’s all fun working on this 49 Chevy truck. I appreciate those members who have the patience to help other members in need. Have a great day.

To Tuts49. I did follow the video which was very helpful. Yes I did measure the disc width and the pads see my initial post. Anyway I have solved the problem. I rechecked the caliper bracket installing correctly with the grease fitting on top as directed. This was not the problem because it was installed correctly. The calipers needed to be compressed which I did. The discs still were tight and barely turned with all my might. Meantime I just slightly sanded the pads and this was enough to get the calipers assembled on the disc, turning with a little drag. Thank you.

Glad it worked out for you. I learned some time back that these “Kits” almost always require tweaking of some sort. Sometimes you just got to do what you know will work and not worry about warranty returns. If we didn’t modify stuff we would never accomplish the task at hand.🛠

^^^^^^^^^^^ this x100............”bolts right in” is myth plus if it.............bolts right in ........it would take away half of the fun.

Very COOL. You'll think your driving a Go Cart the way it will stop. I'm adding a Hydro Booster to mine, that's still in the fab stages so I'll let you know what happens. BTW gorgeous truck

Thanks Tuts!

I finally wrapped up the disc brake conversion. All set, right? I proceeded to bleed the brakes starting from rear wheel passenger side. 2 rear wheel were no problem. However when I tried to bleed the 2 front disc brakes (with bleeder pump) I could not get any fluid to flow. I checked reservoir and it was full. I then proceeded to manually pump brake pedal. The fluid did flow. The passenger hose leaked at the connection of hose to caliper. I rechecked . The hose is held with a bolt and 2 copper washers. There are 2 sides to the hose connector. I made sure the flat side faced down onto the caliper as was directed. . I disconnected and reattached. Tried pumping the brake again. Still a substantial leak. Any idea out there what’s going on? Thanks to all members who offer a helping hand to a novice!

Here’s a little better pic.

I'm sure you do BUT is there a copper seal on both sides of the fitting? As far as bleeding the caliper, are the on the correct side? if the caliper is upside down you won't be able to bleed it. I struggled with this on a Jeep CJ5 years ago, I had the calipers on the opposite sides. They looked correct but the bleeder was not in the right location.

Hard to tell but ill give you something to look at. Looks like you have the hose clocked at say 12 o'clock. It appears that it should be turned to the say, 9 o'clock position so the hose fitting sits flush against the caliper body. At least from the pic, it appears that, thats where the body is lower to give the fitting room to allow the hose fitting to fit flush against it instead of cocked.. Hard to tell not seeing it in person...

Okay. The caliper is position correctly with the bleeder valve up and the 2 copper disc on the banjo bolt. However in looking closer I mistakenly assembled the bolt with the flat side facing up away from caliper. It should be flat side down in this way the bolt will completely seal the line. I’ll re-assemble tomorrow and it should be fine. Thanks for your comments.

Not sure what exactly that means, "flatside of bolt" but regardless, dont let the master cylinder empty itself or you may have to bleed it tomorrow also.

One side has a flat edge the other is off the flat. Thanks for the suggestions 👍. I’m paranoid about MC emptying while bleeding and I frequently check.

Check your copper washers for deformities from being installed incorrectly. Generally they can be problematic when trying to get multiple uses out of them. I do not know what the torque specs are for those banjo bolts are. I tighten them as tight as I can with a 3/8" drive ratchet wrench. I am not a gorilla, BTW. If they leak after that, I will go will a 1/2" drive ratchet and go a little tighter.
I avoid starting the process with the 1/2" drive ratchet because you can snap a bolt or bugger up the treads if you aren't careful.
Admittedly, this is shade tree technique, but I hate working in the sun.
Carl

Copper washers aren't meant to be reused, but a trick to make them reusable if you have to is to anneal them. Take a propane torch and heat them red hot and let them cool off. It softens them up enough so that they can seal as second time.