Slickster Posted November 23, 2020 Report Share Posted November 23, 2020 New to me 48 P15, going through brake system, looks like someone was into it last week, but has been sitting for 5-10 years, new hoses, some new shoes etc....rebuilt front and rear wheel cylinders, and master cylinder, good brake action, but pedal got firmer the more I drove, rear brakes seriously dragging, rear drums hot after 2 miles, replaced rear brake hose, when I cracked the fitting where the hose connects to the body, the brakes were free, so pressure remaining from master cylinder?....pulled master cylinder apart, nothing obvious, there is a valve assembly in the cylinder, defective? Residual pressure valve? Do I need that? Will attend Daytona Turkey Rod Run....maybe try to pickup new master cylnder....anybody else going? Quote Link to comment Share on other sites More sharing options...
kencombs Posted November 23, 2020 Report Share Posted November 23, 2020 Make sure you have free play between the push rod and piston at the master. Most common problem with your symptoms. Piston never uncovers the hole in the bottom of the master. 2 Quote Link to comment Share on other sites More sharing options...
Slickster Posted November 24, 2020 Author Report Share Posted November 24, 2020 I have about 1/4 inch of freeplay, also the relief hole is clear....short of replacing master cylinder, not alot of options, rebuild kit was from Argentina btw.... Quote Link to comment Share on other sites More sharing options...
kencombs Posted November 24, 2020 Report Share Posted November 24, 2020 1 hour ago, Slickster said: I have about 1/4 inch of freeplay, also the relief hole is clear....short of replacing master cylinder, not alot of options, rebuild kit was from Argentina btw.... 1/4" at the rod,or pedal? Old hoses sometimes fail internally and act as a one way check, but you say yours look new, so? There should be a residual valve in the master, and should have come with the kit. It could be defective, but that should make both front and rears drag. Quote Link to comment Share on other sites More sharing options...
Sniper Posted November 24, 2020 Report Share Posted November 24, 2020 I had a problem with my brakes dragging that turned out to be the pedal assembly wasn't returning properly, due to lack of lube. I could pull the pedal up with my foot and the dragging stopped, so my son and I lubed the brake pedal pivot and worked the pedal to free it up. Quote Link to comment Share on other sites More sharing options...
Slickster Posted November 24, 2020 Author Report Share Posted November 24, 2020 There is freeplay between the rod that depresses the master cylinder piston and the piston itself, there is residual pressure coming from the master cylinder....both fill and relief holes are clear....what else could it be besides the valve thing in the master cylinder? Maybe remove it and see what happens? Quote Link to comment Share on other sites More sharing options...
Slickster Posted November 24, 2020 Author Report Share Posted November 24, 2020 And the brake lights stay on, eventually go out....... Quote Link to comment Share on other sites More sharing options...
kencombs Posted November 24, 2020 Report Share Posted November 24, 2020 24 minutes ago, Slickster said: And the brake lights stay on, eventually go out....... That proves the presence of residual pressure. If the hole in the master is truly uncovered when at rest, (immediately after applying and releasing the brake), the residual valve or hoses are suspect. I suggest using the brake light as a method to help troubleshoot. Take the cover off the master, watch the hole and fluid while applying the brakes. The light is on, release brake and see if there is a relationship between when the light goes out and fluid movement. I think I mentioned the possibility of a defective residual valve. Never seen it happen, but with a new part one can't be sure of anything anymore. Quote Link to comment Share on other sites More sharing options...
Slickster Posted November 24, 2020 Author Report Share Posted November 24, 2020 I drilled a tiny hole in the check valve, bled the system with my vacuum bottle, seems like it's working, no brake drag, no brake light staying on, decent brake action...not sure what to think....did find that the left front brake had ridiculous bed springs on it instead of actual brake springs, nearly impossible to remove, and I have all the right tools... Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted November 24, 2020 Report Share Posted November 24, 2020 11 minutes ago, Slickster said: I drilled a tiny hole in the check valve, bled the system with my vacuum bottle, seems like it's working, no brake drag, no brake light staying on, decent brake action...not sure what to think....did find that the left front brake had ridiculous bed springs on it instead of actual brake springs, nearly impossible to remove, and I have all the right tools... If the springs have floating hooks that is what Andy Berbaum shipped me and when asked they stated that is the correct spring. I don't know if it is or not but it works. Quote Link to comment Share on other sites More sharing options...
Slickster Posted November 25, 2020 Author Report Share Posted November 25, 2020 Three of the wheels had non floating type springs, typical effort needed to remove/install....one wheel had springs that look like that...WAY too tight....able to get them off with alot of effort/swearing....no way were they going back on, needed to be stretched 2 inches or so....adapted random springs to work, will order new springs Quote Link to comment Share on other sites More sharing options...
'41 Fat Bottom Girl Posted November 25, 2020 Report Share Posted November 25, 2020 For what it's worth, here is something I ran into with a similar drum overheating problem. It didn't get better after bleeding the brakes again, resetting all of the shoe adjustments, making sure return springs were good, and then suspecting my master cylinder- but that seemed fine. What I found? I had replaced my wheel cylinders about 8 years before that during a brake overhaul, and then left the car sitting until I had it on the road again. Over that time, it appeared there must have been some condensation that developed inside a few of the wheel cylinders on the outside of the piston travel, and caused just enough corrosion that the piston cups weren't always retracting all the way- and two drums got so hot in driving that it discolored and peeled the paint off two of my drums (I had painted them during that brake job). I also had one that started to leak, which caused me to check out the wheel cylinders, and that's when I found my problem. Curious, because I had made sure when I did that brake job on all four wheels that I had lubed the full bores of all the cylinders with some fluid as I assembled them- I guess that wasn't enough. Would never have had the problem if I had been driving the car after the brakes and wheel cylinders replacement. I replaced all the wheel cylinders, and all has been fine since. May not be your problem; just an FYI. Good luck. Quote Link to comment Share on other sites More sharing options...
Frank Elder Posted November 26, 2020 Report Share Posted November 26, 2020 I would not run Lockheed brakes without having brand new slave cylinder's honed and sleeved then you never have to worry again. Quote Link to comment Share on other sites More sharing options...
Slickster Posted December 5, 2020 Author Report Share Posted December 5, 2020 So everything was working for a couple of weeks, brakes are dragging again, getting hot, only driving a mile, if I crack a bleeder on the front, the front brakes free up, adjusted pedal freeplay to 3/4 of and inch just to eliminate that, brake lights stay on until pressure bled off, ordered new rebuild kit from AB, not one from Argentina, residual valve not right?, there are only two holes looking down into the master cylinder? A large one and a small one? Both are clear....any thing I haven't thought of? Quote Link to comment Share on other sites More sharing options...
'41 Fat Bottom Girl Posted December 5, 2020 Report Share Posted December 5, 2020 Hmmm.. maybe more info might help a bit: 1) Which ones are dragging- Right front, left front, right rear, left rear? Are these the same ones as you first found not releasing properly before? 2) You mentioned cracking a bleeder on the front- were both fronts dragging and cracking a bleeder on only one free up both? Or did you have to crack bleeders on each wheel cylinder? 3) Which of the wheels appear not to be dragging? Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted December 5, 2020 Report Share Posted December 5, 2020 It might be your brake shoe return springs: according to my master 1937 thru 1952 Tristate Moapr catalog there are two different sets of springs us on your car: I located both of the sets currently on ebay: Front Dod, DeS chrysler 46-52 Part # 854059 rear same cars and years 46-52 Part # 854049 Both of these are found on ebay for 19.00 by frank Mitchel part. these return springs are not the floater style inwhich the hooked end can move inthe coiled spring body. So take a look and search by the part number supplied. Not sure what AB sent you but at least you can verify with the pictures that are on ebay. Rich Hartung The Parts catalogs are a vintage car onwers best friend and this is why I purchased them over the years to make sure you have the correct part for your cr. A parts seller will always tell it will fit but I alwasy go by a specific part number when requesting a part. I have this catalog on CD if you are interested. Rich Hartung desoto1939@aol.com Quote Link to comment Share on other sites More sharing options...
JBNeal Posted December 5, 2020 Report Share Posted December 5, 2020 I thought I knew purty much everything about brakes, then I had to deal with an aging ABS on The QuadCab...kinda sounds like ya might have rubber components that have swollen from brake fluid contamination and multiple components are dragging, maybe hoses are constricting...there was one line in my shop manual that mentioned that complete component replacement is required for all components that have rubber internal parts when brake fluid has been contaminated, and that's what I had to do for calipers, hoses, MC, etc...it fixed that slow returning brake pedal after months of furcurking with it piecemeal Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted December 5, 2020 Report Share Posted December 5, 2020 What a rubber brake hose looks like after succumbing to long-term attack by brake fluid: 1 Quote Link to comment Share on other sites More sharing options...
Slickster Posted December 5, 2020 Author Report Share Posted December 5, 2020 The hoses are new, wheel cylinders and master cylinders were honed, cleaned and cups were replaced, front and rear were dragging.....3 wheels had non floating typs of springs, seemed like it took typical effort get them off and on, left front had floating type...hard to believe all the springs are weak? I'll drive it again and crack both the lines at the master cylinder, if the wheels release, residual pressure in master cylinder? Quote Link to comment Share on other sites More sharing options...
JBNeal Posted December 5, 2020 Report Share Posted December 5, 2020 Thus is the insidious nature of swollen brake rubber: the force applied to the brake pedal could be 200#, but the drag of swollen parts + the constriction of hoses kicks in and the various return springs cumulatively might only have 100# of force, so the hydraulic pressure releases slowly instead of almost instantaneously when brake pedal force is removed. Driving the car might duplicate the problem, but it may be time to inspect each brake part more closely. Even with new parts, damage may occur from brake fluid contamination. So starting with the MC sounds like a good approach, but physically inspecting each moving part might be in order. This is how I found out the depth of my brake problems on The QuadCab, by comparing how much effort was required to move caliper and MC pistons by hand with replacement parts. The caliper pistons varied in how hard it was to re-seat them, and none were as easy to re-seat as replacement calipers. The MC showed similar variation during bench bleeding compared to its replacement. At this point, my suspicions of brake fluid contamination were confirmed, and I went ahead and replaced rubber hoses, etc. flushed out hard lines with brake cleaner and compressed air, and power bled the system. It was tedious, messy, and kinda $$$ but the brake issue that I had fought for months was resolved...in that link I posted, I also touched on the importance af proper lubricant used on critical parts. As I told a lady friend who could not wrap her head around why I was doing so much work on that old buggy, brakes are like being on a see saw: if one person is too hefty, then neither have any fun...the big kid can launch himself up a little, but the little kid doesn't balance him enough to teeter on the bar, so the big kid doesn't really go far (unless he tries to launch the little kid into orbit by cannonballing the see saw, slamming his end into the ground, then jumping off real quick if the runt is still on his end, just to be a jerk). This is kinda what's happening in car brakes, with the brake pedal applying force to energize hydraulic circuits, then the return springs de-energize the hydraulic circuits to complete the balancing act. Quote Link to comment Share on other sites More sharing options...
Frank Elder Posted December 5, 2020 Report Share Posted December 5, 2020 3 hours ago, Slickster said: The hoses are new, wheel cylinders were honed. But did you have them sleeved? They will just pit again if not sleeved. Quote Link to comment Share on other sites More sharing options...
kencombs Posted December 5, 2020 Report Share Posted December 5, 2020 In an earlier post I thought you stated that you drilled a hole in the residual valve? If so, it's not likely that the valve is the cause, unless if was drilled in the wrong place. It is also possible that there are 'steps' or grooves worn into one or more backing plates that keep that shoe(s) from returning every time. Quote Link to comment Share on other sites More sharing options...
Slickster Posted December 5, 2020 Author Report Share Posted December 5, 2020 The wheel cylinders were not sleeved, just honed, cleaned up and new cups installed, I did drill a 1/16 inch hole in the residual, that seemed to resolve the problem..for awhile..pretty sure there is pressure left in the brake lines..going to replace the valve with parts from AB.... Quote Link to comment Share on other sites More sharing options...
Slickster Posted December 16, 2020 Author Report Share Posted December 16, 2020 Got it! Started from scratch, drove car, brake pedal got firmer and firmer, brake lights stayed on, put car up on 4 jackstands, all 4 wheels really dragging, sucked juice from master cylinder, took a 1/32 drill bit and stuck it into tiny drain back hole, fluid shot up about a foot! All wheels free, I remember blowing out the two holes while rebuilding the master cylinder, but I probably just jammed more crap into it...when I let car back down, it just about rolled out of the barn by itself...thanks to all the assist....now to deal with loose steering and moderate death wobble.... 3 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.