So I got my truck running decent and got all the lights working correctly but the brakes seem to be sticking. When i apply the brakes they work great but they stay on after I take my foot off the brake. Even the brake light stays on. All the shoes and cylinders seem to be in working order. There is a return spring on the cylinder shaft that retracts fine but the pressure doesn't seem to be releasing. I'm thinking the inside of the cylinder is rusty and not letting the plunger retract. I have bled the brakes until clear fliud runs out of all four wheel cylinders. I first thought the brakes were adjusted too tight so I backed them off till the wheels turned freely but one drive around the block and they are sticking again. I'm thinking master cyl. is my next item to replace. Any ideas to try first? Thanks!!! Ron..
have you tried pulling up the the pedal, first i guess is your running the stock setup where the pedal is mounted to the trans by a shaft cast the the side of the trans? if your setup is the same as my 45 gmc i think you can look at the end of the master and see if the piston is all the way out.
The pedal isn't stuck down. I will have to look into the end of the mast. cyl and see if the piston is stuck. And yes it is all stock.
i'm not thinking the pedal is stuck, just it might not be returning to it's stop, just reach down and pull up in it, you should not be able to move it at all.
Tried it but the pedal returns just fine. Haven't been underneath yet cuz its dark when i get home from work. The overall consensus is that the master cyl is bad. I ordered a rebuild kit for it. Figured i would rebuild it and see. I hope it solves the problem!!! Thanks!!! Ron..
Drive it and then jack one or both front wheels to see if it they will turn. We had a similar problem with our 36 and it turned out that the brake hoses were bad. The fluid wouldn't return because the inner diameter of the hose had collapsed. If after checking as I mentioned in the last paragraph, the brake is applied, crack the bleeder valve. The wheel should now turn, if this is the problem. I would check this out before rebuilding the master cylinder.
Had the same problem with my '38. Tracked it down to the tiny hole in the master cylinder that bleeds the system back into reservoir being plugged. Take the cap off, press the pedal down and make sure that there is a tiny jet of fluid shooting up when you let off the pedal.
Ok, so I rebuilt the master cylinder and got it mounted back up. Gonna bleed the brakes tomorrow and see what happens. Wish me luck!!! Ron..
Well...still got problems. I put the new parts into the master cylinder exactly in the order i took them out but it is still not working correctly. Its is pumping more fluid out the front than to the wheels. It was obviously wrong to begin with. Where can i find a diagram of how the guts go in properly? I did a little searching but didn't find anything on the web. This is getting frustrating!!!! The rebuild kit didn't have any instruction sheet in it either. I had to walk away from it today. The simplest looking master cylinder ever and I can't get it to work!!! grrrrrrr!!!! Ron...
Yeah!!! I took the cylinder apart and flipped the piston around. Brakes pumped right up!! Bleed the system and we are cruisin!!!!! Works perfectly now!! Sometimes you just need to step back and breathe!!! I found a diagram on american classic trucks website. So my $17.99 rebuild kit was all I needed. That and some patience hahaha! Got almost all the bugs out of it now. Still stalls at idle once in a while but I have never even taken the carb off so thats next for now. Can't wait to upgrade to a later six in this thing!!!. Ron...
Well I apparently spoke too soon. Went for a cruise today and after about 10 minutes the brakes are doing the exact same thing. The pedal is all the way to the top and the brakes are staying on again. Even the brake lights stay on after I park it. They worked great for 10 minutes then right back to the same thing. I did notice that the pedal when it was working pressed down about 2-3 inches but once it started sticking again now it only goes down about 1/2 inch. I checked the reservoir and there is a little stream of fluid coming back into it when I release the pedal. I also checked the frt brake hoses and they look like new. When i had the master cylinder apart it was perfect inside and out. Not a spot of rust anywhere. Even the cylinder bore itself was a nice polished finish to it. Maybe there is a little ridge in it I didn't see. I am going to take it apart and hone it out and try it again. This is so frustrating!!!!!!! Ron..
Yeah I tried that today. As soon as I opened the frt bleeder all 4 wheels loosened up. I jacked it up today and every wheel was locked until i bled off a little pressure. Then it rolled freely. It is pressurized in the whole brake system. Enough to make the brake lights stay on. Its gotta be the master cylinder not releasing the pressure somehow. When I had it apart i saw that the hole between the cylinder and the reservior was clean and flowed easily. When I bled the brakes it dropped the level in the reservoir so I had to keep it filled to keep the air out. I would think if the hoses were bad only the front wheels would lock up. Is that what yours did?
What happened to ours was the inner part of the hose collapsed and wouldn't release the pressure to the front wheel. It happened on both front wheels. I had never had this happen to me before. Replaced the front hoses and everything was good.
About fifty years ago, I tried rebuilding a master cylinder. If didn't work for me and since then I just replace them with either a rebuilt or new one. I rebuilt my own wheel cylinders until the mid 1970's and then it wasn't worth the time for what you could buy a new one for.
I went ahead and ordered all 3 brake hoses. Even if this is not the problem it is a good safety item to have new ones of. Hopefully this will solve the problem!! If not I guess a new master cylinder is next!! Thanks for all the help Ron...
When it locks up break the line at the mastercylinder loose and if it releases then you know it is the master.If not go down the line until it frees up.I have seen rust stop up a t fitting and lock up the brakes as well.
How much play is in your pedal to master clinder? It will do exactly as you are saying if there is no play.....
KJSR is right, you need need a little free play on the pedal or it won't bleed off the brake pressure. I went round and round with this same problem with my 52. I checked for check valves in the master, replaced calipers, hoses, and even installed a heavy duty return spring before I realized my plunger was being help in too far and blocking the return port. Sent from my DROID device using the TJJ mobile app
KJSR and Skippycraig got it right. Your brakelight stays on, because there is a pressure build up in the master. Could be the check valve in the master, but its more likely a lack of play between the pushrod and the piston in the master.
That sounded good!!! So i adjusted it to about 1/4 of play and unfortunately it is still the same issue. I was really hoping that would solve the problem. Which part of the master cylinder do you think would cause this problem if it is the cylinder? This is an exploded view of it: http://www.americanclassic.com/partdescriptions/BR0201.html Thanks!!! Ron..
Pretty sure the master doesn't have check valves in the outlets like a modern dual would. My buddies 55 wagon had one of the small ports between the reservoir and where the plunger bore. rusted shut and wouldn't fill the bore. We took off the outlet fitting and blew air backwards out of the reservoir, would also tell you if you have check valves. Sent from my DROID device using the TJJ mobile app
Now that I think about it air just blew fluid all over the garage, we used a small drill bit or a welding tip cleaner I can't remember. But if the return port is plugged it would be slow to release the pressure. Hope my babbling helps, Craig Sent from my DROID device using the TJJ mobile app
So was there free play the first time you adjusted it? Sometimes it takes a few adjustments to get it right. Bottom line there is only three things that would cause it to happen. a misadjusted mc rod clogged brake hoses or lines (this is normally the case when you have only one front wheel or both back locking) crap in your mc/piston not returning correctly/mc assembled wrong/missing spring, etc If you are positive you dont have an issue with the first two you need to look hard at the mc. i would be happy to look at it for you if you want to ship it over to me.
Another way to test if its a pedal issue is to recreate the issue and while the brakes are locked, disconnect the brake pedal linkage. If the brakes free up the adjustment is the issue....
I did pull the pedal away from the master cylinder and it didn't change anything. I had pulled the dust boot out of the way so I could see the plunger and it is all the way forward. The push rod is about a 1/4 inch away from it now. I may take you up on the check of my mast. cyl. Let me try those new hoses when they get here and if that doesn't fix it I will send it to you for a check up!! Your awesome!! Thanks again for all the tips everyone!!! Ron..
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