Front disc brake conversion on '69 Scout 800A

S

swebby

New member
We have '69 Scout 800a with a dana30 front axle. The conversion kit we have came from Scout parts. We bought it off an individual who said they found they couldn't use it because they didn't realize that their stock 15" tires wouldn't fit.

They bought it for a '73 Scout II. It all bolted up to ours easily, with the exception of one brake hose on the driver side not being correct. We were able to get a correct hose and everything seemed to be ready to go, with the exception that the brakes would never pump up all the way.

We tested the master cylinder by plugging off all the hoses and found the cylinder would hold pressure. Then we alternately plugged front and back, and with either offline, it would hold as well. Put them both online and it wouldn't hold.

Seeing that IHPA sells a new cylinder with their kit, we thought that might be the issue. Can't understand why scoutparts doesn't mention it tho.

We just got the new master cylinder for the disc conversion from IHPA and plugged it into place tonight. Same thing.. Brakes won't pump up.

The only thing left is a new proportioning valve? Before we throw more money at this tho, I wanted to check to see if anyone thinks we missed anything else.

Also would like to confirm that the larger side of the new mc goes to the front disc and the smaller side to the rear drums. We have to criss cross the lines to make that work.

Is it possible that there was more that was different in the kits than meets the eye? If the kit we got was a good fit physically, could there be anything going on with the calipers, etc that wouldn't be compatible?

Any help would be appreciated. Having to wait a week for new parts in between trying things is getting really frustrating.

Tia..
 
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Since the 69 originally had drums up front, the oem master cylinder and proportioning valve were for that setup. If neither of those were swapped out when the disc brake conversion up front was done, then I bet that would be the culprit. Contact the good fellas at IH Parts America and they will set you up in the right direction.

I personally don't purchase anything from that other place. But I did check out that brake kit. It looks like the master cylinder and proportioning valve are not included in the kit. And they should have stated the fact of new ones would be needed with the conversion
 
Thanks. We did get the master cylinder from the IHPA conversion kit, but not the p valve.

Seems like we should still be able to get pressure, even if it's not distributed right. We'll call then Monday and see if they can shed some light.

Thanks again
 
Two things I can think of are caliper clearance to the knuckle and proper installation of the caliper. Normally grinding of the knuckle is required for proper clearance of the caliper. If you didn't do any grinding than most likely that is your problem. Also make sure the calipers are installed on the correct sides which puts the bleeder screw on top. If the bleed screws are pointing down than that means you have the calipers installed left for right and need to swap them. You also might find it beneficial to read our direction sheet as it might provide a clue as to what is wrong and has detailed pictures of where you need to grind.

CPT s80/800 front disc brake installation instructions
 
I think that might be it! We didn't get the instructions with the set.

I'm going to order the pv this morning. Sure wished we gotten your kit, but that deal was hard to pass up.

Thanks so much for the response!
 
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