62 Lesabre Dual Master Conversion

[62Lesabre]

Hey all. Recently bought back a 1962 Lesabre 4door I had sold 6yrs ago. One of the items I had hoped would have been addressed in between ownerships was the brakes. I’ll start with what I did the first time owning it 

 

car has original 4wheel drum brakes. I was having difficulty at the time figuring out why the brakes were so terrible so I started replacing parts

 

all new shoes, wheel cylinders and hardware. Including at least the two front rubber hoses. Had the front drums turned. 
 

Vehicle was a NON power brake setup from the factory. I decided to add power brakes. I even found the correct firewall bracket and brake pedal. I used a bendix booster and bendix master cylinder from a 1967 Buick with drum brakes. 
 

when I owned it I could not for the life of get the brakes to bleed.  They would not gravity bleed. I tried a brake bleeder kit but I felt that I never really could bleed them correctly and got it about as good as I could which wasn’t very good. 
 

fast forward 6yrs later and the brakes are worse now. I’m going to try and bleed them again then I’m going to start replacing parts. Any ideas? 

[JohnD1956]

If you have a manual, I would suggest looking for the procedure to adjust the main pin at each wheel. Then do the "major brake adjustment" procedure. 

 

While everyone probably has a different story to tell, on my 56 I had the parking brake cable too tight. This prevented the rear brakes from releasing fully and impacted the adjustment of the shoes.  

 

In addition, some have said that today's "over the parts counter shoes" are less effective than having your old shoes relined.  While I have not found this to be completely true, my 56 does have power brakes, which may help.  Here are two more things to consider:

1) having old shoes relined offers the opportunity to have new shoes arced to fit the respective brake drum.  This should result in full contact of the shoe with the drum when the shoes are properly adjusted.

2) in the case of my 56, the over the counter shoes hardly worked when I test drove the car.  It was a big disappointment  and a scary situation when the car did not want to stop.  But driving the car around the block several times, with frequent application of the brakes greatly improved the performance quickly.  I believe this is known as burnishing the brake shoes. After about 200 miles I was finding I could lock up the brakes if I needed to.  

 

Besides this I also understand that putting a different master cylinder and power booster in may require relocation of the brake pedal and the rod used from the pedal to the master cylinder.  The factory location is designed to produce a certain ratio of pedal travel to rod travel.  This will be needed for effective deployment of the master cylinder.  In this case using 67 parts with your 62 bracketry may be resulting in an improper balance in this regard, or not enough brake rod travel to fully deploy the master cylinder. 

 

I also might ask if you bench bled the master cylinder before installing on the car?  Some units require that step, although I think that is mainly for the MC's that sit on an angle when attached to the power booster. I know in my 69 "A" body the manual master cylinder gravity bled with no bench bleeding required. That MC sits level when mounted. 

 

Another thought is you may just have a bad master cylinder.  

[drhach]

Drum brakes are more finicky about being adjusted properly. Also, as suggested, you may need to get the shoes arced. Something I've done in the past is to take a sharpie a draw lines every inch or so across the shoes. Go for a drive and then look at the shoes. You'll see where the pads are contacting and where they aren't. If the pads aren't arced properly, you won't get full engagement.

 

The factory manual has a pretty good procedure for brake adjustment. 

 

Maybe have a pro vacuum bleed the system? 

[60FlatTop]

Sam will help you out: https://www.rochesterclutch.com/

 

Pick a letter of the alphabet and you can stop as farther as we know; B, J, O, S, R.

 

Step one, remove the improvements.

[62Lesabre]

Here’s my update. Went back down memory lane with this headache but I did confirm I purchased the Bendix booster and matching Bendix master cylinder for a 1967 Lesabre with drum brakes. Took the master cylinder off last night and bench bled it, figured I’d start at the beginning and work my way down. Here’s a photo for reference of it off. 
 

I have the rear MC port going directly to the rear brake line bypassing the factory splitter. The front MC port going to the top of the factory splitter and then added a short line and fitting with the brake switch attached to where the rear line came out of the factory splitter. Does that sound right?

Edited September 21, 2022 by 62Lesabre (see edit history)

[Frank DuVal]

The "splitter" is just a switch itself, between two separate paths of hydraulic fluid. If one side has pressure and the other does not, the switch lights a dash lamp to let you know there is a brake system failure. If you put pressure into the front section and connect the outgoing brake line to the rear section, it won't work right, and Bernie is then right, putting the stock system on will work better! 

 

Since I "assume" you did not mount a dash brake failure light, skip the switch assembly and buy a small actual splitter to connect the two front brake lines to one of the master cylinder ports ( the other port is where the line to the rear attaches) and either also have a port for the brake light switch or mock up a mid 60s under dash brake light switch (or an early 50s Chevy brake light switch that works off pedal movement under the car) and skip the pressure style brake light switch.

 

Also to others reading this, the switch block is not a proportioning valve. It is just a differential pressure switch.

[62Lesabre]

The factory splitter is nothing more than a way for the one brake line to split off to the front and rear brakes(originally). There’s not wiring to it. The way I have it set up right now the front port of the master cylinder goes to that splitter. The rear port is directly connected to the rear brake line. 

[EmTee]

So, there's currently no differential brake pressure (i.e., 'BRAKE' light) switch?  Is the 'splitter' you're referring to the one that was there originally to feed the front wheel cylinders?

[62Lesabre]

The brake light switch is attached to where the rear brake line would connect to that splitter on the frame rail

[62Lesabre]

I think at this point maybe it’s easier to just replace the master cylinder with a single port unit. Interesting to see there’s hardly any 1962 full size Buick master cylinders but if I look for 1963 riviera there’s some out there. I would assume they would be the same MC? 

[usnavystgc]

1 hour ago, 62Lesabre said:

I would assume they would be the same MC? 

They are very likely the same or similar enough to use but, with Buick, you never know.  Maybe @NailheadBob could help us with all of his literature on parts.

[NailheadBob]

On 9/22/2022 at 10:37 AM, usnavystgc said:

They are very likely the same or similar enough to use but, with Buick, you never know.  Maybe @NailheadBob could help us with all of his literature on parts.

The Buick Master parts book shows: for Master Cylinder

 

group # 4.650 1962 and 1963 with regular brakes part # 5462563 for 4400 and 4600 series

 

1961 and 1962  part # 5457094 with Power Brakes 4400,4600,4800 series

 

1963 part # 5467565 Power Brakes for series 4400, 4600, 4700, 4800

 

Bob

Edited September 24, 2022 by NailheadBob
update (see edit history)

[62Lesabre]

Bench bled the master cylinder. Re installed and bled all four wheel cylinders. Upon start up initial brake pedal was perfect. Pedal progresses to the floor after any initial pedal press and loses pressure. All the way to the floor. I’m pretty sure at this point that the master cylinder is leaking/failed internally. First press is perfect, holding the pedal will slowly go to the floor and not hold pressure.  Ordering a new one today. 

[62Lesabre]

Issue resolved! It was the master cylinder that had failed. Was leaking internally. Bought a new one, for a 1967 Lesabre with 4wheel drum brakes and bendix booster. Found a new Dorman unit. Bench bled and installed and brakes work, no loss of pedal and brake lights work off the pressure switch. Yay!!!!! I will bleed at the wheel cylinders to make sure all air and old fluid is out but I FINALLY have good brakes on this old girl. 

[drhach]

Great news!! Post some pictures of the car. 

[62Lesabre]

Here’s some photos. All but one are from the first ownership. My bellflower tips were removed in place of an obnoxious flow master system (previous owner) that I will

be getting rid of and going back to a stock exhaust. The Regal behind my car in the one photo is my dads that he bought new in 1978 and has stored every winter since new. 

[JohnD1956]

Very nice. Interesting Regal. Would like to see more of that if possible. 

[drhach]

Great pics. I've been wondering what a white roof might look. It's looks fantastic. I have a set of that stainless window trim in my attic waiting to be installed. Glad you got your car back. I hope you're enjoying it.

 

 

Edited September 29, 2022 by drhach (see edit history)

[62Lesabre]

I always liked the white or even two toned roof on the B/C bodies. My roof is actually vinyl covered. Not sure if it’s factory or not but it’s in amazing shape so I’m leaving it alone. 

[Machine Gun]

22 hours ago, JohnD1956 said:

Very nice. Interesting Regal. Would like to see more of that if possible. 

Me too. My first new car was a '78 Regal.

[clintas12]

@62Lesabre

I've got the same car, and having problems with my brake pedal being ridiculously stiff, standing on it wouldn't even make it budge! 

I've been looking hard for a new brake master and booster, where did you manage to find yours?

[EmTee]

How old are your brake hoses?

[62Lesabre]

On 4/2/2023 at 8:06 AM, clintas12 said:

@62Lesabre

I've got the same car, and having problems with my brake pedal being ridiculously stiff, standing on it wouldn't even make it budge! 

I've been looking hard for a new brake master and booster, where did you manage to find yours?

When I bought the parts I believe I purchased the booster and master through AutoZone. This would have been around 2015 so not sure either are still available. Went with a booster and master from a 1967/68 Lesabre to get the dual system but still for drum brakes. When I bought this car back the master cylinder had gone bad and was able to find another to replace it 

[Frank DuVal]

On 4/2/2023 at 8:06 AM, clintas12 said:

problems with my brake pedal being ridiculously stiff, standing on it wouldn't even make it budge! 

Does the booster have vacuum on it? No vacuum will make a very stiff pedal.

[clintas12]

On 4/3/2023 at 10:05 AM, EmTee said:

How old are your brake hoses?

They're old lol. 

This cars sat for the last 15 years, it needs completely restored.  I'm having trouble finding alot of the parts, Moreno than expected when I took the project on. 

[clintas12]

On 4/12/2023 at 12:00 AM, Frank DuVal said:

Does the booster have vacuum on it? No vacuum will make a very stiff pedal.

It may have a leak, but it sounds almost internal. I imagine it would need rebuilt. 

[Frank DuVal]

The booster can suck air from the pedal side, you might hear a hissing noise under the dash.  

[EmTee]

9 hours ago, clintas12 said:

They're old lol. 

An internally collapsed hose will give a hard pedal, as well as uneven braking.  Changing the rear hose on my Riviera 'fixed' my power brake booster.  (I assumed the booster was bad, but the bad hose was actually to blame.)