Better braking

[Royal Duke]

While speaking to another 1941 Chrysler Royal owner about the brakes on our cars, I mentioned investigating a disc brake conversion.  He offered an alternative and so I am writing to ask if anyone on here has tried this idea, how it worked out, if you have any photos of the installation or shop manual pictures of it.  What I am referring to is installing a 1953 -54 Chrysler vacuum operated brake booster under the car.  Any and all advice/guidance would be appreciated.   duke

[Hamilton]

In and of itself, an old-technology factory booster might not do much more than to make it a bit easier for you to drag your slow-stopping car to a halt.

 

_

[keithb7]

Are you pretty confident your brake shoes are concentric to the axle/spindle centre? This makes quite a difference. I can't complain about my stock 1938 single MC reservoir brakes. They work fine for the expected speeds back in 1938....Now, if I had added a transmission overdrive and am trying to stop from 70 MPH.....Different story.

Edited October 13, 2020 by keithb7

[TodFitch]

1 hour ago, keithb7 said:

Are you pretty confident your brake shoes are concentric to the axle/spindle centre? This makes quite a difference. . .

 

Absolutely true!

 

If the shoe linings are not arc'd to the drum diameter and if not installed concentric to the axle with proper heal and toe clearances the braking will be horrible. But if they are set up per the original factory service manual they are adequate for the speeds the car was designed to run at. Chrysler Corporation was no slouch in the engineering department and the brakes, properly installed and adjusted, are as good or better than any of the era.

[martybose]

A decade or two ago, I did all of the right things when I rebuilt my OEM drum brakes.  The shoes were arced to the drums and then were adjusted with the Gee-Whiz tool.  But the braking at freeway speeds still scared me, as I was used to the 4-wheel disk brakes on my commute car.  So I installed front disk brakes, and was pleasantly surprised by the improvement.  As always, YMMV.

 

Marty

[49WINDS]

I agree with Tod and Keith, if you get the factory drum brakes set up correctly then they may surprise you how well they can work! I acquired my 49 Windsor earlier this year and instantly started looking at a disc conversion as well. After seeing the cost and amount of work it would take, plus seeing advice on forums like this, I decided to stick with just replacing the shoes,wheel cylinders, & master cylinder. At first I was highly disappointed with how they worked when I put everything back together, but I didn't know how important it was to set them up concentric to the axles. Once I was able to get that straightened out the brakes work great and I can even lock up the wheels if I push hard enough! I guess it all comes down to it you're just going to drive these cars as what they were built for, or if you're more looking to put in a bigger engine for more power/speed/etc and would then need better stopping power. Either way, this forum has a great wealth of knowledge and I'm sure you'll get whatever help you need in working on your car.

[Royal Duke]

My car is original and I am not interested in driving fast.  I am retired and don't need to get anywhere in a hurry.  However, being in the Miami area of FL introduces dangers and crazies that I did not encounter in Connecticut. Not that there aren't crazies in CT, but the ones down here are in a much higher league.  AA in CT versus Major League in FL.  

[Royal Duke]

I think my brake shoes are aligned properly within the drums.  They aren't dragging or anything like that.  I will be installing a new MC which I purchased from Kanter when I get back to CT later this month prior to shipping the car down here.  I was thinking of driving the car down here sightseeing along the way.  For the reasons mentioned in my prior reply and this reply, I just want to get the best stopping power available without changing everything out.

[TodFitch]

7 minutes ago, Royal Duke said:

I think my brake shoes are aligned properly within the drums.  They aren't dragging or anything like that. . . 

 

Not dragging is not necessarily the same as properly adjusted. Getting the shoe heal and toe clearances correct makes a huge difference. And that can’t be done unless the arc of the shoe matches the arc of the drum.

[Royal Duke]

Thanks Tod. I was not aware of that. I may try to get the special tool used to ensure that they are properly adjusted. I know the tool is few and far between and costly if one could even be found.  Joy is.

[Richard Cope]

Many years ago, read an article in which an individual took an extra brake drum and drilled several holes around the circumference and would then use a depth gauge to determine the location of the brake lining in relation to the drum.  Once set, he would replace the drum.  Don't recall where I read, has anyone ever heard of doing so?

[James_Douglas]

I just tossed out two complete sets of the under the floor boosters. I got them complete off of some car in a yard. The problem is that the MC in those corrodes real bad and to rebuild them is darn near impossible as parts are hard to get. Lots of aluminum in them.

 

Go to the Ford Thunderbird parts guys and get the Midland Ross Remote power booster that they sell. It is darn near the same one that Chrysler used on the 300's when they have the cross ram manifolds. They put it under the fender on my 64 300K Ram Induction car.

 

I used that booster on my 1949 Desoto. That was about the only major change from stock I did on it, with the 4 wheel disc brakes. The dame thing stops TOO good.

 

A couple of things to note. ALL the power brake cars in those years used a different brake pedal arm (below the pivot pin) and a different push rod going into the MC.  Different pedal ratio. Again, on my '49 I used one from a 1952 power brake car, a chrysler if I remember.

 

I cut and welded a stainless over pan and mounted the thing in it on the trunk next to the spare. If the thing leaks, the pan will catch it. I have a black plate in the trunk to hide it and nobody, not even the concourse judges ever noticed it.

 

If you use a remote power brake booster, you cannot use a split M/C.

 

James

[TodFitch]

1 hour ago, Richard Cope said:

Many years ago, read an article in which an individual took an extra brake drum and drilled several holes around the circumference and would then use a depth gauge to determine the location of the brake lining in relation to the drum.  Once set, he would replace the drum.  Don't recall where I read, has anyone ever heard of doing so?

 

I’ve heard of that, but with only one hole drilled (you rotate the drum as required to make measurements). However on my car no two drums have been turned to the same exact diameter. And new drums for my '33 are made from unobtainium so I have to work with what I have. I was able to acquire an Ammco tool for a pretty good price years ago so I can adjust for each drum’s diameter as I work my way around the four corners. I count myself lucky on that.

[DJ194950]

Using a proper tool for adjustment of brake shoes also showed me the most likely Chinese shoes I purchased had a slight twist  in the mounting point on one end. This is repairable and was covered in my repair manual, it causes the shoe to not lay flat across the brake drum surface and brakes are not good.

 

After correcting and more adjustment, brakes are super. I found out how well when I had to do a panic stop shortly after and all 4 tires locked up.

As good as it can get.

 

DJ

[Richard Cope]

I had my brakes first done years ago at a small shop, they had a grinder that could be rotated around the brake lining and grind down high spots.  Unfortunately that shop has closed. 

[Frank Elder]

44 minutes ago, DJ194950 said:

Using a proper tool for adjustment of brake shoes also showed me the most likely Chinese shoes I purchased had a slight twist  in the mounting point on one end. This is repairable and was covered in my repair manual, it causes the shoe to not lay flat across the brake drum surface and brakes are not good.

 

After correcting and more adjustment, brakes are super. I found out how well when I had to do a panic stop shortly after and all 4 tires locked up.

As good as it can get.

 

DJ

What.....you don't have ABS....?....lol.

[DJ194950]

1 minute ago, Frank Elder said:

What.....you don't have ABS....?....lol.

 May have helped but the 4 wheel lockup did allow me to get slowed down enough to be able to let off and turn left sharply and not rearend  the stopped car ahead of me .

 

Was driving cross town in afternoon traffic and aggressive driving by all sucked me in also. Now I remind myself that driving any of my cars that I'm retired- What the hell am I rushing for??  ?

 

DJ

[TodFitch]

46 minutes ago, Frank Elder said:

What.....you don't have ABS....?....lol.

 

You mean they no longer teach how to modulate your braking during an emergency to keep traction and control? I am pretty sure that was part of my high school’s driver education and training back in the 1960s. I will admit it needs practice and ABS doesn’t require anything more than just pressing the brake as hard as you can.

[Sniper]

the problem with ABS is that it tends to allow steering control at the expense of stopping distance.  A properly modulated brake pedal will out stop an ABS car, all else being equal.  But there are dang few people that can properly modulate a brake pedal.

[kencombs]

14 minutes ago, Sniper said:

the problem with ABS is that it tends to allow steering control at the expense of stopping distance.  A properly modulated brake pedal will out stop an ABS car, all else being equal.  But there are dang few people that can properly modulate a brake pedal.

Especially with varying road surfaces.  One can practice  on dry concrete, wet asphalt, gravel etc.  And sure as anything the real deal pops up on sandy concrete or something.  I like ABS, sometimes,  steering control may or may not be a priority.  Most people just freeze at the wheel and stomp the brake anyway.   Few even consider steering away from the bumper in front of them.

[Frank Elder]

2 hours ago, TodFitch said:

 

You mean they no longer teach how to modulate your braking during an emergency to keep traction and control? I am pretty sure that was part of my high school’s driver education and training back in the 1960s. I will admit it needs practice and ABS doesn’t require anything more than just pressing the brake as hard as you can.

I think Nick is the only one on this form still in school Tod..........it was in my training the 70's.

[1951plymouth]

If u have several miles on your brakes, you can take the drums off now and use a permanent marker to put some parallel lines on the shoes about every half inch.   Them reassemble and go drive it for 10 to 100 miles.    Then remove drums and look at the lines....if you see lines that part of shoe is not being used.   So there should be no lines on shoes if they are adjusted correctly.   If there are line there is some brake tuning required.