So Ive had problems with lack of performance with mydaily driver 235 '53 belair. Ever since I completed a brake job Ive noticed pretty significant brake drag. Convinced that the shoes were not fitting the drums perfectly, I swapped back in the old shoes. Old shoes were still "ok", I just figured it was time to upgrade the brakes. Seemed fine for a while, or I should say, not as bad. So tonight, I pull in the garage and the car does a nose dive as if I romped the brakes! Im getting tired of this issue, so I log onto the HAMB to try and find some info on this problem. After reading some threads the main suggestion is to loosen the lock nut on the pin to give yourself some play, in the chance that the plunger isnt retacting back far enough to clear the by-pass or bleeder port. So I slide under to see if I have some adjustment. NOPE! Theres surprisingly no adjustment to be had with any of it. No elongated mounting holes, solid plunger shaft and this is the reservoir that the brake and clutch hinge from. I decide to remove the master cylinder and inspect it for debrit or anything obstructing the flow design. Heres what strikes me as odd. The diagram below shows (basically) my master cylinder, less the adjustable piston rod. You can see here the two ports illustrated at the bottom of the resevoir. After, cleaning up the parts, I made sure the two ports were free. By the way, I purchased a brand new master cylinder when I converted to a 3 speed, So its not the old grimey one. And now that Ive been thinking about it, Ive had a bit of drag off and on. Well guess what? The by-pass port was not drilled all the way through. I thought it was just blocked at first, but I ran my finger inside the cylinder and theres only one hole! Heres a picture with a LED flashlight pointed down into the resevoir and heres a pic looking down into the resevoir I pretty sure Im on the right track with my problem, but hearing it from someone that really, truely knows these brakes would be a help. So heres my question. Is the cause of my brakes dragging related to this by-pass port not being open? If so, would you recommend exchanging it for a new one, or drilling it out? Thanks
All 4 brakes drag. All lines are good. When I removed the brake pedal from the resevoir, the wheel spun free since presssure was released. Im curious if my hunch is correct about the by-pass port not being open. Thanks
When I was in the trade years ago we would disc a slight taper on the ends of the brake linings so that there wasn't a 90 degree end. I was of the view that the end expanded slightly as opposed to the rest of the shoe. The ends may have expanded due to heat and drag on the drums?
I had the same problem with the MC on my 55 Olds. I rebuilt the MC and my brakes were still locking up so I replaced just about the whole brake system and the problem was still there. After thinking I put something in the MC the wrong way I took it all apart again for the 3rd time and that is when i discovered that the return hole was rusted shut from the bottom (you could not tell it by looking at it). I replaced it with a new MC and the problem went away, I thought about drilling it out but was worried about the diameter and if the hole was tapered so, that is why i went with a new one.
how are you adjusting the brakes? are you turning the adjuster out till you just barley hear them touch? or is it a solid brake drag? sometimes on the older cars they need to be adjusted a little loose to account for everything heating up. its happened to me before, adjusted them out a bit and drove it for years.
The return hole is the problem, all right. The line pressure has no relief and heat buildup expands the fluid, making the brakes drag. My '54 has a good cylinder, and that little hole gets an air bubble in it when bleeding the brakes, and no way I can get anything to happen without a pressure bleeder. One little thing can cause all kinds of grief! Be careful to get the right size drill, you don't want to make the hole too big.
Replace the master since you know it's defective. When you get a new one, take it apart (always) and check for damage, defects and foreign matter. Flush if needed with denatured or isopropyl alcohol, and assemble with clean brake fluid. Now would be a good time to think about switching to a dual master, IMO
The schematic shows adjustment and lock nut @ the apply rod, removing the the apply rod releases the brakes? Some masters I have encountered require some preload on the apply rod or pumping required even with bled brakes, too much preload results in what you are seeing. I found the adjustment to the apply rod to be VERY subtle, I'd work with that before buying another master.
Thanks go to apparatus, bobss396, r pope and v8 bob for reading my question and just answering my question and concerns for the by-pass port. Ill be purchasing a new MC and inspecting it. Ill upgrade to dual MC later since this is a daily and want to get it on the road soon. Thank you all for your input!! HAMB rules again!
Also, be sure that your brake pedal assy. is releasing completely. I had a similar problem with a '68 Ford pick up, the longer I drove it, the more the brakes would drag. After a bunch of expensive guessing from "experts", I found that the nut secureing the stop light switch was too thick to allow the pedal to completely release, thus causing a build up of pressure as a drove and used the brakes.
Better off with the dual-master, which will open NEW and improved problems, nothin' that can't be solved here. Bob
What a bizarre, one-in-a-million problem! Please let us know the results after drilling or replacing the master.
ill definately let you all know the results. I went to my old car parts guy today and he has a reconditioned one that he will swap me for exchange. He said it has been resleeved with a stainless steel sleeve, but he wants to hone it for me tomorrow to make sure its all true. I was able to look into the resevoir to see the two holes. The inlet port is larger than my "old" one, but the by-pass port has a tinny tiny hole. I dont even think I have a bit that small. Good thing I didnt try and drill it out. Ill post pics of it tomorrow when I get it back. Bobss396, do they even make a dual resevoir for the 53-54 set up? Ive never seen one. These MC bodies have two pivots that the brake pedal and clutch pedal rotate in. If I were to convert, would I go with a 55-57 set up? I dont even know what those look like, let alone how to custom fit it to my application. Thanks
Update! So After looking into my options, (after the by-pass port was confirmed never drilled at the factory) I looked into a dual resevor upgrade. After reading a bunch of tech DIY threads and discovering a reman dual res was under 15 bucks, I went for an upgrade! Just bled the brakes tonight and went back and forth inside the garage. They stop HARD! And no brake drag! Yahoo! I can push the car in neutral with one hand now, compaired to before. I had to put both feet on the work bench and push the hood with my back. Say NO to brake drag!! Cant wait to see how my MPG will change for the better!
Exfuckingceptional job! Anyone with a similar ride should save these pictures. And it looks almost factory... nah but it works like gangbusters. Bob
drill it out.... run a hone. and call it a day... should fix the issue ... all drum brakes drag a small ammt just how they are..meaning hearing the pad against the drum barely scraping... but it the wheel is hard to turn then you got more of an issue.
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