brake shoe arching

just four new drums and shoes for my 51 Chevrolet convertible. does anyone know of anybody within 2 hours of Chicago that has a machine to arch brake shoes with

If the drums are new, and the shoes are new, they should not need re-arcing. Place the new shoes inside the new drums and see if the lining touches the drum all along the length of the shoe lining.

GLong

Is the 1951 a powerglide?

Yes

Sent you a PM

Now we will never know what the secret PM message has to do with the possible PG brake job.

Inquiring minds really want to know!

I just wanted to give him some information about someone who is doing it for me right now. I do not know if I would be violating the rules of the site by posting his name and number on the thread, so I just felt it would be safer to PM him the contact info. I also did not have time to give this detailed answer at that time so it was easier to PM, sorry not keeping any secrets, I was just busy, sorry.

As far as the powerglide, I never have heard of this until the last few months, that is when I bought my first early powerglide car, in the buy/sell section of this very same site. The early Powerglide cars had/have a real bad reputation of not being able to stop well at all! The guy I purchased the car from was a very honest man and I wish everyone I had ever bought a car from was a true as he was to his words! He told me that he did most of the mechanical work on the car including the brakes, but he was not happy how they stopped the car. Well he was right, and I don't like it either, as a matter of fact I hate it! Spoke with some of my fellow Chevrolet friends who are more familiar with these years then me. Some said that is the way they are, they just stink! Some said the modern brake shoe material could be a problem and do not work as well as the old cancer causing stuff, and I should replace the linings on the shoes. Makes sense to me I remember reading in the theory section in a 1960 Buick shop manual about how different brake material compounds can have an effect on braking. So I located this year at Hershey a set of good old asbestos linings. The guys who said change the shoes also said to cut my drums and have the shoes arched. I am in the process of doing that now. The shoes are getting riveted and will be arched once I get the car to my other home in Florida and have access to my lift, I will take the drums off and have them cut, and get a final radiaus measurement for him. My days of jack stands are over, my knee(s) can't take it.

The problems I can see stoping the early Powerglide Chevrolets are caused by a combination of things. The transmission does not upshift or downshift on the 50 through 52 models, the powerglides also have a 3:55 rear end ratio so when you are slowing down to brake there is NO ENGINE COMPRESSION assisting the effort guided by the transmission downshift. Also making the 1950 worse is they still use the "huck" brakes, they changed to Bendix in 1951, however I have heard they are not much better. One other suggestion I was given was to replace the master cylinder with a 53 or 54, they have 7/16" bore rather then a 1" bore. The smaller the bore the higher the pressure to the wheel cylinders.

Back when I was kid in the mid to late sixties my old man used to buy these car every few weeks for 50 bucks and use them as commutor cars from our home on Long Island to the Bronx where he worked. I remember being up in the Bronx visiting my Grandparents and he saw a real clean 50 Fleetline four door, and as we were walking up the car he said "forget it's a powerglide" I never asked I just thought they were bad units, little did I know. He bought plenty of 54 powerglides, but never any 50-52 cars, never put it together

Are the wheel cylinders, brake drum diameter and shoe width the same on the powerglide cars as on the manual shift cars ??

If so, I'd see if just sliding the shift lever into N when braking helps any.

The friction of the shoe material has a great effect on the brakes. All of my pre-WWII cars have mechanical actuated brakes. And if modern

lining is put on instead of the early woven high friction lining, there is a noticable increase in pedal pressure required to stop.

As mentioned, a smaller diameter master cylinder will increase the hydraulic pressure to the wheel cylinders, and if there are larger diameter

wheel cylinders available, that will help too. And high friction brake material.

For the original posted question: I'd take the new brake shoes. set them inside the new drum.. Use a .006" feeler gauge to slide between the shoe and the drum. Since the lining is new, it will not have worn the 'fuzz' off the lining yet, and the fit against the drum will not be perfect. But you should be able to see and feel using a feeler gauge if the lining has a significant gap in the middle of the shoe, [touching the drum on each end of the lining] or has a gap at the ends of the lining, and touching in the center.

I'd check this, it should be easy and quick with both the lining and drums new, and clean.

I'm really curious if the new lining is or is not a good fit, could you try this and report back?

Thanks,

GLong

I have read of the chevy PG cars not stopping correctly. I also agree some modern day linings do not work well on some cars.

I remember when abestos was mostly eliminated back in the late 80's and the heavy trucks would not stop well out asbestos type shoes.

Correct matched shoe fit to drum and lining type is critical for prpoer operating brakes on the old cars.

I don't know the answer to proper lining type as the make up of linings keep changing because of the EPA.

There are problems with converting huck to the bendix brakes, and it requires much more parts then just bolting on new wheel cylinders. Backing plates and such have to be changed, 25 years ago I would have been able to find some that I could use..... the supply is that much older and rusted now.

I don't think shifting to neutral will give the desired gear reduction needed to slow down, and I don't think manual shifting to low is all that healthy for a 60+ year old automatic.

I will report back once done, but deep down I don't have my hopes all that high. In a book I have printed in 1954 they said that the brakes were bad, when the old style material was in use. At the very best I expect it will be a little better, but not that much. Everyone said I could stomp on the and they won't lock up.

My 53 stops great, that has a three speed. My son's 54 with a powerglide not nearly as good as the 53 but much better then the 50

I doubt that every or even most manual shift drivers of this model chevy uses aggressive down shifting to augment the foot brakes.

What I've found in many of the early emissions-controled cars, that the carburetors had a dashpot that made the carb slowwwlllyyy go to idle when the driver let off the pedal. This had a noticeable effect on the braking effort needed to slow the car.

Even today, with a vehicle with an automatic trans, if you are on ice, it will stop MUCH better if you slip the trans into Neutral, because the trans is pulling the car along most of the time at lower speeds.

With my '20's cars, I have found that the high friction, woven lining is noticeably better.

Since the OP is in the Chicago area, maybe a call to Ft Wayne Clutch would be in order, they have all the old lining materials or modern replacements with similar friction coefficients.

I'm wondering if a good search for the later bendix brake backing plates and parts wouldn't be worth the effort and wait, if the 'huck' brakes are

so bad?

Anyway, best of luck with improving your brakes.

GLong

thank you a 51 already has bendix brakes just trying to get the shoes arched to the drums

They changed to Bendix in 51, from what I was told they are better but still not that great. I was also told in 53 they did go to a wider shoe and different drum, that would help a 51 & 52, bot you would need to find those drums