single wheel cylinder front drum conversion

[Guest 50Plymouth]

Okay, why would anyone not remain either bone stock drum, or go to modern disc?

Yet I couldn't help but wonder if anyone has ever remained front drum but converted to a more modern single WC. (I like to consider pointless possibilities, it keeps me busy .. I have no idea when the dual front wheel cylinder went away. I'm considering all options on my p20.

Has anyone ever converted to single WC front? I suppose I'll remain stock or go disc but was curious.

Ryan

[Guest Nile Limbaugh]

Actually, Chrysler went from a single cylinder in the late thirties (I have it on my 37 Dodge) to the dual cylinder in the early forties. Considering the trouble I've had in getting my cylinders to seal and getting the shoes adjusted, the only thing I would consider at this point is a disc conversion. I even thought about changing to a floating shoe system like GM had but the difficulty of finding a 10" system to match the old drums is too much to think about. IMHO the biggest problem with the old Mopars is that lousy brake adjusting system.

[Guest 50Plymouth]

Interesting, I didn't know they used single previously. Even if I went front disc, wouldn't I still have the 'adjusting issues' with the rear drum?

I hate to buy 6 new WC total if I don't keep stock long term. And I am skeptical that rebuild kits will work\not leak upon initial inspection of those old WC. So finding 10" single drums that can be used on our beloved old mopars is a no, I didn't know if that meant even new spindles or what all.

[Plymouthy Adams]

looking for the silver bullet in the arena of brake vampires..no real easy way out here..I have not explored anything but the obvious kits that have been worked up by builders already covered on these pages and magazines. At the moment they seem to be the basic choices..price, amount of customer interventionin assembly will be the two main factors deciding which way to go. If you gonna spend the money to upgrade, I cannot see keeping drum brakes on the front..for the rear they are still ok for operation but then..the ole adjustment trick is in play. Lots of people also upgrade rear gears to modern unit that have floating shoes..self adjusting and all the good stuff.

You may be the one to get out there and did in the j-yards and pioneer the newest upgrade to keep the old shoes in place..just don't see the advantage.

I rebuilt my cylinders..not a problem..Advance has the kits...very cheap may I add...I have the parts to upgrade to disc now..just a matter of having set aside the time to whoop them on...

[Jim Yergin]

On my '41 Plymouth I went with disc brakes on all four wheels. AAJ Brakes sells the set up. Having the e-brake on the transmission makes the conversion that much easier.

Jim Yergin

[grey beard]

Dodge pickup trucks all have single wheel cylinders up front. You might find an easy retrofit there. AND, to make the cheese more binding, these pickups use two wheel cylinders on the rear axle, just back asswards from cars. Go figure . . . . . .

[PatS....]

On my '41 Plymouth I went with disc brakes on all four wheels. AAJ Brakes sells the set up. Having the e-brake on the transmission makes the conversion that much easier.

Jim Yergin

If you use Cadillac calipers in the rear disc kit, you get ebrake as well.

The Cadillac calipers incorporate ebrake into the caliper which will bolt onto the same bracket.

You get to keep the original rear, updated brakes and modern ebrake. Not bad.

And all easily reversible to stock.

[Guest 50Plymouth]

Dodge pickup trucks all have single wheel cylinders up front. You might find an easy retrofit there. AND, to make the cheese more binding, these pickups use two wheel cylinders on the rear axle, just back asswards from cars. Go figure . . . . . .

What total year range are we talking on the Dodge pickup's?

Was using 2 wheel cylinders somehow cheaper for the manufacturers at some point? I mean unless it was touted as 'superior' or 'safer' it was just more work for the factory.

[Guest Nile Limbaugh]

The reason for two front wheel cylinders is that the type of brake used then wasn't self-energizing. My old (1937) one cyl. system has 4 different cylinders, one for each corner of the car. Each had two different bores because, with the shoes not self-energizing, the trailing shoe did very little work so the wear was uneven. The 2 cylinder front system made both shoes self-energizing and eliminated the problem.

[Norm's Coupe]

First of all, I'll never waste my time rebuilding a wheel cylinder again. I never had lasting success in the 60's and I didn't have lasting success on my P15 coupe either. Always ended up buying new cylinders within a year or two tops anyway because the rebuilds would crap out on me. So......IMHO spending the money on rebuild kits is a total waste of money.

If you want to stay with original brakes, I would buy all new wheel cylinders. They are still available through NAPA and various other sources like Kanter, etc. I would also stay away from old NOS cylinders. Who knows how old the rubber is inside and the cups are.

In addition, if you are even thinking about the possibility of disc brakes, don't waste time or money now on anything. Make up your mind before you do the first brake job. For just a few dollars more, you can have nice disc brakes when you weigh all the cost for new cylinders and shoes, etc. So make up your mind the first time and only spend the time and effort once.

Just my two cents worth on this subject. Been down that road. I wanted disc brakes to begin with but didn't want to spend the money. So! First rebuilt my old wheel cylinders. They craped out after just a couple of years.

Then still trying to do it on the cheap, I bought all new cylinders and did another brake job. Still wasn't happy in the city traffic with drum brakes. So. Then spent the money to upgrade the fronts to modern disc brakes. They work great and should have went that route the first time. Would have saved a lot of work and money.

Not trying to sway you in any way toward one system or the other. Just trying to make you think hard before making a decision either way.

[teardrop puller]

Pat S

Do not forget to use the ebrake often. If you do not use it the calipers will not stay adjusted and they will no longet stop. I had this problem on my Jeep and had to replace the calipers because I screwed them up trying to adjust them off the car, I now pull the ebrake a few times every time I think of it, The other day my front brakes on the Plymouth quit, Loose fitting and lost the fluid, and the rear brakes did stop the car and the teardrop that was attached.

So please use the ebrake

kai

[Guest 50Plymouth]

First of all' date=' I'll never waste my time rebuilding a wheel cylinder again. I never had lasting success in the 60's and I didn't have lasting success on my P15 coupe either. Always ended up buying new cylinders within a year or two tops anyway because the rebuilds would crap out on me. So......IMHO spending the money on rebuild kits is a total waste of money.

If you want to stay with original brakes, I would buy all new wheel cylinders. They are still available through NAPA and various other sources like Kanter, etc. I would also stay away from old NOS cylinders. Who knows how old the rubber is inside and the cups are.

In addition, if you are even thinking about the possibility of disc brakes, don't waste time or money now on anything. Make up your mind before you do the first brake job. For just a few dollars more, you can have nice disc brakes when you weigh all the cost for new cylinders and shoes, etc. So make up your mind the first time and only spend the time and effort once.

Just my two cents worth on this subject. Been down that road. I wanted disc brakes to begin with but didn't want to spend the money. So! First rebuilt my old wheel cylinders. They craped out after just a couple of years.

Then still trying to do it on the cheap, I bought all new cylinders and did another brake job. Still wasn't happy in the city traffic with drum brakes. So. Then spent the money to upgrade the fronts to modern disc brakes. They work great and should have went that route the first time. Would have saved a lot of work and money.

Not trying to sway you in any way toward one system or the other. Just trying to make you think hard before making a decision either way.[/quote']

Norm: I think that's what I needed to hear. Did you retain stock rear drums setup then? Did you go with a universal under floor MC? What about combination valve ect.,

I've done two disc conversions on a later make so I know its worth it, but those conversions were quite cheaper since no $200+ adapter plates for the spindle were required. The $7 kit is so tempting but I suspect it would fail (plus having 6 rebuilt WC is really playing the odd's I guess)

4 x $30 front WC + 2 x $50 rear WC brings a total of $220 - never mind MC, shoes or hardware. So I will work at trying to use that to justify upgrading perhaps. If there was some 'easy shortcut' to use single wheel cylinder drums front and rear I might've considered that.

Are using old original front springs an issue with front disc, or would any nose dive be indicative of bad proportioning only?

Ryan

[Norm's Coupe]

Ryan,

I retained the original rear wheel brake system. That's only two new wheel cylinders involved there. I used a disc conversion kit from ECI http://www.ecihotrodbrakes.com/index.html With their kit you don't have to change or machine your spindles. It's a complete bolt on kit. I'm still using my original master cylinder (been rebuilt). However, if you want they do make a bolt on dual master cylinder that keeps the original brake pedal setup and uses the same original mounting. I did have to install residual valves in the brake line. Their kit does not require any spacers either. You don't even mess up you alignment when you do the swap. Easy swap.

Others on the forum have used a kit from Ply Do, AJ Brakes and a forum member (Olddaddy I believe) also makes a kit. Those kits you have to drill out one of the holes a little larger to make them fit. Plus, they also use a spacer on the axle shaft. As far as cost between the kits. ECI looks like the most expensive up front because it's a complete kit. By the time you buy all the stuff required (pad, rotors, calipers, etc.) for the other kits, the cost works out to about the same, give or take a few bucks.

I also retained the original springs, etc. I have no nose dive at all, even in a hard stop, and they'll stop on a dime.

The nice thing about the ECI kit is, if someone wanted to switch back to the original drum system, they can. Don't know why they would want to though.

[Guest 50Plymouth]

Thanks Norm. Got the ECI catalog sent recently. So do many guys use the stock MC with a brake upgrade? Its tempting because the rebuild is so cheap to do.

[Norm's Coupe]

Ryan,

Based on postings on the forum in the past, I believe most people are using their original master cylinder. A couple have gone with power or dual, but most have their originals. Maybe some of them will chime in on this thread. There were a lot of postings on this subject about a year or two ago.

I will add this. I had my master cylinder rebuilt when I first bought the car in 1995. IF I had converted to disc at that time, and IF ECI had that dual master cylinder at the time I would have gone that route instead of rebuilding my old one. ECI just came out with that dual master cylinder about 1 1/2 to 2 years ago. If my original master cylinder goes out again, I will buy their dual master cylinder. It's safer that way.

[Guest 50Plymouth]

So proportioning is not an issue when using stock MC? I'll have to check if those using newer dual MC need prop.\combination valves. Thanks for the info, I'll search for those old threads.

[Norm's Coupe]

Ryan,

The proportioning valve is not necessary with the original MC. You won't find the threads concerning this on this forum format. You'll have to go to the Forum Archives because most of that information was on the old forum format. Or, you could order a CD from GTK and get the threads that way.

Also if you call ECI they will confirm that most people do not use the proportioning valve. I know that Don Coatney and John Mulders also converted to disc brakes. Don used the Ply Do system and John used Olddaddy's system. I don't think either of them used a proportioning valve either. James Douglas of the forum converted his DeSoto to disc brakes using a special kit from ECI. I believe he used a proportioning valve. I think he also went with power MC too, not sure. At any rate, you can "Private Message" those people.

If you call ECI, they are very helpful on the phone. They will tell you what is required with the dual MC.

[junkyardjeff]

A friend took the brakes off a 64 new yorker I parted to use on a 57 plymouth as the 64s were the bendix style,could those brakes be installed in the mid 50s on back models. Jeff

[martybose]

Although I'm sure that a late model disk brake is much more powerful than our OEM drums, and thus will work better than the drums, my bet is that even with a disk/drum setup you won't come anywhere near achieving the braking force that you could achieve if there was a proportioning valve installed.

The primary purpose of the proportioning valve is to get the front and rear brake systems working at their maximum efficiency at the same time. Factors to be dealt with include the fact that disk brakes can use (and generally require) higher brake line pressure than drums, weight transfer during braking, differences in tire diameters or widths, etc. Without a proportioning valve, you will typically lock up the rear drums a long time before you are using the front disks to their full potential; a proportioning valve starts limiting the pressure rise to the rear drums while allowing the front disks to go up as much as possible.

So while a front disk conversion will work better than the OEM drums without a proportioning valve, the car will be able to stop a lot quicker with a properly calibrated (BIG CAVEAT THERE!) proportioning system.

Marty

[martybose]

As a point of conversation, the road race cars that I work on generally require about a 60/40 split in line pressure to stop well, assuming the same size brakes all of the way around. Or to put it another way, the front line pressure is 50% higher than the rear line pressure.

Marty

[Guest 50Plymouth]

In regards to having or not having proportioning, I was surprised to hear the car could operate without and not have front dive issues or rear lock-up, but some guys clearly have it working.

Maybe the stock MC just puts out lower PSI than the calipers expect? I've only done one front disc conversion on another make car, and had major front dive and imbalance until I used a combination valve.

Ryan

[Norm's Coupe]

Ryan,

As mentioned, I get no dive or rear brake lockup. When I first put the disc brakes on I tried to make them lockup and it didn't happen. Also, I did a few hard stops without my hands on the steering wheel to see if there were any issues there too. Car stopped fast and straight as an arrow. All the testing was done on an asphalt street.

[Guest 50Plymouth]

Oh I believe 'ya. Must work so well because of the bore size and pressure of the OEM master cylinder. I wonder what would happen with a later dual, or disc MC, maybe a matching valve setup would be more critical then.

[Guest 50Plymouth]

How does one disassemble a single piston wheel cylinder anyway? I've soaked mine and want to inspect pitting just for fun. Stubborn pistons. Air pressure?

Ryan

[Norm's Coupe]

You can try air pressure but that may not work either. As mentioned I originally rebuilt my wheel cylinders so had to get them apart. Couldn't even get the rear cylinder pistons out with air at the time, or push them out.

If air doesn't work. Heat the casting up with a propane torch so it's nice and hot. Then let it stand to cool until you hear a little crackling noise. As soon as you hear that start tapping the cylinder on the concrete floor, with the open end facing the floor. You may have to repeat that several times but eventually the piston should start to come out.