My 39 P8 arrived today. After a quick learning session on how to start her, i went for a ride around our lot.
She starts and drive really well, idles so nice, shifts well, clutch good, steering a bit loose needs to be addressed. Then i hit the brakes, my lord you need to stand on the pedal. It will stop but distance is so long I don't think it's safe to drive.
I put her in the air. Seems all the wheels stop turning when you hit the pedal. No wet backing plates, pedal is hard, goes about half way down. Does this sound normal for a 83 year old car? I see there are brake upgrade kits available, disc brake might be nice.
Steve
I am not familiar with the brakes on a '38 but if they are like the brakes on the earlier Plymouths in addition to the brake shoe adjusting cam there is an additional adjustment that is used to center the shoes on the drum so that they make full contact. Just adjusting the brake shoe adjusting cam will not work if the anchor pins are not adjusted properly because only a part of the shoe will be making contact with the drum resulting in poor braking power. There is a tool for making the adjustment but it is hard to find and expensive. Ordinarily the anchor pins do not need to be adjusted just to take up wear on the shoes but if the brake shoes were replaced and the anchor pins were not set correctly that may be your problem. Hope that helps.
Soup has mentioned that there are two adjustments, both "minor" and "major". Let me go a bit further. . .
First: When you pulled the drums to inspect did it look like the full length of the each shoe was making contact?
These are drum brakes and for them to be efficient the lining on the shoe (equivalent of a pad on disc brakes) needs to contact with the drum for its full length. If the shoes are not making full contact then you are not getting all the braking you should. If only 1/2 half the shoe is making contact then you are only getting roughly 1/2 the braking.
The proper way to perform a brake job on drum brakes is to fit or grind the lining on the shoe so that it has the same curvature as the drum. This is called "arcing the shoes". In the old days any shop that did brake work would have shoe grinding equipment to do this. My work around is to use sticky back sand paper stuck in the drum (off the car) then rub the shoe back and forth on the sand paper inside the drum until I have even contact for the full length of the shoe. Basically each shoe is ground to match the drum it will be used in. (If you have brand new drums and brand new shoes then fitting/grinding the shoes should not be necessary. But if the drums have ever been turned then you will need to grind/match the shoes to the drum.)
Once you have all the shoes fitted to the drums, then getting the correct heel and toe clearance is important. That is done through working both the major and minor adjustments mentioned by Soup. In the old days there was some special tooling to help with these adjustments. Years ago, over on the P15-D24 forum there were posts on how to make a tool to help so do a brake adjustment tool search over there. Or, if you are willing to take more time than an hourly rate mechanic was willing to do, you can get close working by feel. See: https://www.ply33.com/Repair/brakes
Side note: This heel/toe "major"/"minor" adjustment is because they are Lockheed style brakes. Bendix style are simpler to setup and might actually be self-adjusting. But Bendix brakes can be a big grabby while Lockheed are typically smoother in operation which is why Chrysler used them until the early 1960s.
If properly setup then you should be able to lock up all four wheels.
All that said, they are not self-energizing (Bendix style drum brakes are self-energizing) nor are they power assisted so you will have to press the brake pedal harder than in a new car. But any adult big enough to reach the pedals should be able to lock the wheels.
The one big fault of drum brakes is that they fade when hot. If you are rally driving or racing that is a problem. If you habitually tail gate people and have to jam the brakes on a lot, it might be a problem. If you do long (multiple mile) mountain downgrades and maintain speed by braking rather than down shifting as they did in the old days, then drums can be a problem. But for normal everyday sensible driving drum brakes are safe and reliable.
Thanks for the help guys! I havn't had the drums off yet but hope to at least get the fronts off today. I'll check the wear on the shoes to see if there is full contact or fluid contamination.
It sure sounds like a heal toe adjustment. Like i say, the brakes work but no way they will ever lock a wheel.
I'll get back with what i find. Hopefully i can change the name of the "brace for impact" pedal back to brake pedal! Lol
Steve
I got a chance to get 3 drums off, here's what i found.
The fronts have newish linings but they are worn very strangely. One is worn just on the inner toe and seems to be cocked. The drum goes on easily then drags once all the way on. Both fronts seem cocked. One shoe seemed ok, 3 others have wear concentrated to either the toe or heal. No leakage from the wheel cly but the bleeders look like bolts not nipples.
Got 1 rear off, down to the rivets on 1 the other is all cracked, kinda like it got hot. All the drums look ok.
So, looks like new linings all around and new wheel clys for the front. I did find a place that sells the adjustment tool, maybe a wise purchase for $90.
Not sure if i should machine the drums, they look pretty good.
Steve
It sounds like you have found the source of the poor braking performance, cocked shoes or only contacting on the toe or heal will do it.
The early bleeders have a 1/4" bolt that screws into them which the parts book calls a dust cap. To bleed the cylinder you remove that bolt and screw in a little fitting with the hose. I made a tool out of some small diameter metal tubing and a 1/4" bolt. I drilled a hole through the length of the bolt then pressed the tubing tubing into the hold. I attach a clear hose to this. Installing and removing the tool on each cylinder does slow things down a bit but not by much. If you do not want to maintain the authentic original style and if the cylinders are in otherwise good condition you can just buy new bleeders.
$90 for an original AMMCO 1750 adjusting tool is a steal. Does the seller have a photo of the tool, I would be curious to see what $90 gets you. I am not in the market as I have an AMMCO 1750, just curious.
Carefully measure your drums. If they are anywhere near round I would not turn them even if slightly scored. I am not sure about 1939 but decent drums for 1933 are impossible to find and once they are turned too far they are scrap. Also, turning them will change the diameter and make fitting the shoes that much more important.
I think the tool you found is a new item that is currently being made and is available on eBay. Looks like it would work. I made up something like it years ago. Once you get your shoes relined see if you can find a place that still has a machine to arc the shoes in your drums. If there is a brake shop that has been around for a long time near you they will probably have one laying around in a corner and they might even have someone working there that still knows how to use it. You can try to do it yourself but it is a time consuming endeavor.
I got lucky, just found the OE tool from a place in Ca for $65. It looks well used but complete.
Is there a source for parts we like or hate? Found a couple but havn't contacted any yet.
Andy Bernbaum
Moparpro.com
Mobile parts- Craig Studnick
Steve
For parts I generally try to get as many as I can from my "local better auto supply". The one with the old guys behind the counter and maybe even paper catalogs. These are getting more and more rare though. But if you have one in your area, please patronize them as they need customers to keep in business.
The down side of trying to get your parts locally is that their computers are set up for searching by year, make and model and don't usually list things for cars as old as ours. That is why I built up my parts interchange database which you can access at https://www.ply33.com/Parts/numeric
If you find that one of my cross references is no longer good, please let me know. And if you find a modern part that interchanges with our old ones please let me know too as I'd like to add that to the database.
For brake parts, I have always used the local brake and friction company for where ever I was living at the time to reline my existing shoes. Clutch disk and pressure plate too for that matter. Most of the brake cylinder rebuild parts are very common and should be available locally with the possible exception of the dust boots. I think I got my last wheel cylinder rebuild kits, which included the proper dust boots, from Roberts Motors.
Companies get bought and sold and existing companies have turn over on employees so the vendor that was great a few years ago may not be so great now. And vise versa. That said, I have had good experiences with Then And Now Automotive (a.k.a. Antique Auto Parts Cellar).
That is a great tool, the parts interchange.
I've tryed in my local area and really can't find anyone willing to help. I did find a clutch shop to rivet my handbrake lining.
As far as the brake shoes i've learned that you can still get asbestos shoes, really glad i asked! This brings a new respect to working on whats on the car now.
Plan on getting front and rear shoes, handbrake cable, handbrake lining, plugs, wires, condenser, wires and cap for now.
Goal is to have the service brakes working and a backup with the hand brake.
Next has to be repairing the steering box. A rebuild kit came in the car. Dosn't look like a fun job.
Steve
Hey all, need a little more help. I'm in the process of replacing the front brakes.
I see in the manual and the stamping on the cly's confirm right and left placement with the small piston forward. When mounted like that the brake hose face's the rear of the car.
This makes routing the hoses hard.
In the manual pic's number 19, 49 and 54 show the hose coming out towards the front of the car, this makes way more sense. But if i mount them this way the small piston will be in the back. By chance are these Chinese wheel cly's machined wrong?
Steve
Don't know the answer but would not be surprised. I ordered new wheel cylinders for my car that were supposed to be correct but were far from it. Admittedly I could have made them work but I sent them back and had my wheel cylinders bored and sleeved. Much happier with that result but my cylinders were single bore so I am not sure if yours could be repaired similarly.
I wish i had the option of rebuilding mine. Both of mine seem to be wrong, one has the hose problem i mentioned the other one seems to be from the rear. The hose on the "rear" one is in the right location though.
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