my 1940 Plymouth just will not stop. I have spent a lot to try and make them safe, to no avail. After spending over 1k replacing everything, still nothing. Decided it is time for Disc Brakes. Some of the kit's look rather "cheap". So tell me want kind of success anyone has had with certain conversions, good or bad. Thanks in advance.
Something is wrong either with your parts, your install or adjustment. Those brakes worked fine when the car was new and for years after. More details and someone here can help.
My 40 Pontiac coupe with stock brakes would lock all the wheels easily and stop great any time. Find out what is wrong and fix it. Get what ever help you need, it is not rocket science. Gary
I agree. Get a reprint shop manual and adjust/bleed the brakes as stated in the book. They are relatively cheap online and you will probably not have to spend any more money on the brakes.
If it's all new parts to the tune of 1000 bucks I'll bet it's a ratio problem. That is****uming the parts are installed correctly. Bore ratio or pedal ratio
I think old Plymouths use a version of Lockheed brakes, and probably have TWO adjustments on each shoe. Procedure should be in shop manual, if I'm right about the type...basically, one of the adjustment systems centers the shoes in the drum and the other tightens them up...they are BOTH used when new shoes are put in, then only the upper one. Whatever it is, follow the manual and make no****umptions based on post 1956 bendix designs. Then, the next biggy...should have been first! drum to shoe fit. Ideally, shoes would go on, be rough adjusted, and then cut to match measured diameter of drums. Do-it-yourself way would be to place shoe into drum and see if curve matches drum. Home ways to fit involve use of hammer to re-arch shoe (requires experience with violence) or to simply grind away a bit at either center or ends of shoes, depending on direction of misfit, until approximately right so some minor driving can finish the job. Misfit there is VERY common and absolutely kills brake surface area in use. Problem isn't always wear...some manufacturers do things like making shoes to fit a worn drum on the****umption that older cars are worn out, and of course such shoes will contact only at ends on good drums. Your brakes should be at least adequate, and if they aren't they need normal mechanical*****ysis and fixing.
You do have to make two adjustments on each shoe. with the eccentric at the bottom and then the minor adjustment at the top. I think it may be covered in the 1946 Motor manual I have at home and I'll try to remember to look when I get home. Here is link that should help though. http://www.btc-bci.com/~billben/brakeadj.html
Having the right linings is necessary too. There are different types of friction material. The friction ratings should be on the edge of the lining but sometimes they are painted over. Metallic linings will require much more pressure. You need to know how much pressure you are getting at the wheel cylinder. Get a brake pressure gauge and see what the service manual says it should be.
Thank all of you for your response to my "Lousy Brake" story. Yes, I agree that it is traditionally an easy procedure to do a brake job, I have done some in the past. I do have an original Service and Parts manual for the '40 p10, I have talked to many people about this brake issue. I have installed a new MC, replaced 2 wheel cylinders and kits in the other one's, new pistons , new springs, new caps, new brake bleeder screw's, some new lines and fitting's, and caps. The part about spending so much was that I got frustrated and took it to a local Rod @ Custom shop to have it fixed correctly, no such luck. I was unaware of the brake pad issue, but did adjust the brakes as stated in the Manual. They honed the wheel cylinders, which I had not done. There a no leaks in the system as of now, but the Pedal goes almost to the floor before the brakes try to work. We were going to a car show the other night and a car pulled in front of me, I pushed the pedal and nothing happened. I was sure I was going to hit the car ahead of me, but was able to move into the adjoining lane just in time. So now I don't drive it because of the safety matter. I will be discussing the problem to the shop that did the work and hope that something can be done. Try, try, again! Thanks
Don't depend on the local rod shop to know any more than you do. Something is not right here. I know you bought a bunch of parts but don't gloss over the part about properly adjusting the shoes and fitting them to the drum. Also, as mentioned, check the bore sizes of your master cylinder and you wheel cylinders and make sure that they are correct. If the ratios are off, that will cause a problem. I know you're frustrated but you can do this! Keep a clear head, think logically, and do one thing at a time.
if the pedal goes to the floor its one of 3 things , Bad master internal seal ( bore worn so bad or honed out too large without proper oversized cup placed in it and fluid is leaking past cup on piston till it hits a smaller Diameter spot in bore ( happens a lot on masters rebuilt at home , as people wind up reboring there masters not lightly hone them ) or (2) shoes not tight enough to drums and its taking alot of take up fluid for shoes to touch ) . or (3) the cylinders are too large for the master stroke ( people using oversize cylinders trying to up pressure on shoe) and taking up too much fluid displacement , this is rare but does happen.
Look very closely at the wheel cylinder pins. Sometimes you get the wrong length and it really messes things up. Stimpy is correct, too.
You said when you pushed the pedal nothing happened. But what happens when you pump the pedal in rapid succession? Even a problem system that needs shoes adjusted, has a bit of entrapped air or leaks a little fluid should give you some braking when you "pump" the brakes. If not, you likely have a problem with your master cylinder, as stimpy said.
Residual pressure valves ? A Pedal going to the floor is very different than not having good braking efficiency. Without pedal pressure there's no chance of any braking at all.
If you are going to convert to disc try ECI hot rod brakes. Great product and service. I did my 50 dodge. On a side note the 36 dodge brakes i have seemed a better system than the double slave i replaced on my 50. Always wondered why they changed. Good luck and keep an eye on the rubber hoses they can cause much grief.
When I bought my 37 Plymouth the guy I got it from had pretty much the same story....all new parts and a ton of $ but still no brakes. A simple brake adjustment gave it awesome brakes. If you pull your parking brake lever is your pedal any better?
Jack the car up and have someone turn one wheel at a time while you depress the brake pedal. If the wheels don't lock up you have a air bleed problem.
If you can't get those type of brakes working properly. I'd hate to see what kind of problems would surface installing disc.
A friend had poor braking on a 37 Plymouth. The previous owner had replaced the front brake line with tubing that was too large to get the proper pressure.
Agree that you should be able to get good brakes on it. My first car was a 40 Plymouth coupe and never had any problems with the brakes. It is important that the shoe arc fits the drum arc but that won't cause the peddle to go to the floor.
Hydraulics do not work that way. Properly bled, you could have a 4" diameter brake line and it would not matter. At every single point in a hydraulic system, regardless of brake line size, is exactly equal.
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