Need Some help diagnosing brakes

[Justjake88]

Hey all,

I have been creeping this forum for a few years now but only needed to post recently. I have a 1968 D200 camper special with power brakes, I have done a full rebuild on the engine and wanted to refresh all the brakes. I have replaced all wheel cylinders, master, booster, and the lines from the master to the T on the frame rail. Now after having some issues with air in one corner I replaced that new wheel cylinder and the line from the rear T to that corner (the 16" hard line). My current issue is I have a good pedal engine off, and with the engine on the pedal has no resistance until halfway down, the brakes work and work well but all of the braking is in that no resistance range so I have no feel to my pedal. I have felt spongey brakes before but I thought I remember a little resistance on spongey this is like non existent but for only half of the pedal travel.

I am going to try to adjust the booster side of the pedal rod out some more and see if that helps ( while adjusting the M/C rod as well )
I have tested the M/C with brass plugs to rule that out, it was a little soft re-bench bled and it is hard as a rock.

I have a hard time believing there is still air in the lines as I have put so much fluid through the system and I was not seeing any on my final run.

Any other ideas to try would be helpful. Also if you all have the stock bore sizing for wheel and master cylinders so I can compare would be great as well, everything I have come up with is 1-1/8" on all of it.

[powerwagon54]

Did you turn the drums? Do you have the shoes in the proper position? If yes to both of the questions, sounds like an adjustment problem.

[Kaegi]

I think you ar on the right track. the push rod adjustments make a big difference in travel. 1 1/8" bore is correct I am fairly sure

[Justjake88]

I believe I have the shoes in the proper positions, the drums did not get turned as the fronts were new and the rears had no issues (surprising). I adjusted the rods and I can get used to the pedal while driving but it just feels like the booster is doing all of the work and there is still no real resistance. This morning I drove it and the pads were too far out after pulling the e-brake once and were dragging I did not have an issue driving it home so I assume the e-brake just pulled the pads too close and didn't release fully so i am going to pull the rear drums off again and readjust (again haha). I can't wait to do a disc conversion.

[Kaegi]

shouldn't have to pull drums to adjust drum brakes. there is a hole inthe backing plate. adjust until you can feel just a slight resistance when spinning wheel. if you spin wheel hard it should spin about one revolution if shoes are adjusted right. try to achieve the same amount of resistance at every wheel.

[Justjake88]

Yeah I know you dont have too, but I have found that adjusting them out is easy back in is a pain. Anything I should check for the e-brake causing issue with adjusting? I cant think of anything cable pulls and releases I may just be too far out and its not coming back in. Last i would think maybe that rear flex has failed and its not letting pressure back but I have not determined that yet.

[PwrWgnDrvr]

No such thing as "too far out", unless the drums are oversize or shoes worn out.

[Justjake88]

I got it, it just took some more adjustment in the pads and push rod. Brakes work great. Thanks all for your input and knowing I was kinda on the right track here. 2 weeks of messing with the damn system and I can drive it woohoo!

[Kaegi]

great job. under 75 mph the drums should work as well as disk. just higher maintenance. cheap linings give drum brakes a bad name because they heat fade. you can get HD linings installed that are used on emergency vehicles and it will stop like a race car with a load in the bed.