VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1938 Brake Job - Tips?

Just received my new brakes and wheel cylinders from The Filling Station. Are there any tips or tricks that I need to know about when I overhaul all four wheels this weekend?

I saw a comment about things to do when adding new linings... What I couldn't understand is how do you center the linings and then tighten the bolt WHILE the hub is on? I have to assume that you install the hub, step on the brake, and then remove the hub so that you can tighten the bolt?

Thanks for any advice.

Answer to #2---The Huck type brakes used from 1936-50 do not require centering.There is no bolt to do it with either.After shoes are installed the pedal is depressed hard a few times.This centers the shoes by aligning the links-do this before adjusting.

Tips---Seeing that your replacing the wheel cylinders spray a little penetrating oil on the REAR brake line fitting at each cylinder.Aim it at the back of the fitting where the line goes thru.This will help if the line is rusted to the fitting and will prevent it from twisting with the fitting when its lossened.

Seeing your going this far what are you doing about the "rubber" brake hoses??-If they are over 20 years old they also should be replaced.The metal lines are another story.All three hoses are the same.

Lubricate the adjusting threads lightly with"white grease".I also lubricate the metal adjusting cup with silicone grease -outter edge where it contacts the wheel cylinder and grease (silicone) around the piston bore (behind metal adjuster).This helps to seal the air and moisture from the piston-a common caus of the piston rusting to the cyl. bore on Huck brakes.

What are you doing with the master cylinder?If not rebuilding it and it had black sludge on the bottom of the reservoir the system can be flused with 100% denatured alcahol.Chevrolet sold it under the name "Decelene" and was used for this purpose.

Have fun with the little "bend over" retainers that hold the pins to the links etc.Filling Station has new ones if they break.

After the job is completed make a few slow stops from 40 mph to seat the linings-don't lock them up in the first 500 miles.

I assume that you have a shop manual

Take two asprin and call me in the morning.

Thanks Gene. I have a follow-on if you're up to it!!??

My rear brakes have a centering bolt at the top of the rear shoe. I have a Motor's manual that I'm reading. It talks about centering the shoes after new ones are installed. I've read it about 10 times and I'm starting to understand it....
but would still like some confirmation. :confused:

It sounds like they want you to do the adjustments of all four brakes first... then come back and (with the rim off) twist the centering bolt to get the "bottom" of the shoe to kick out as much as you can.

A few years ago, I put new brakes in my '31 Chev and meticulously followed the instructions for centering the brakes... and it made a HUGE difference... they were at least twice as good as previous... so that's why I'm paying a lot of attention to this on my '38.

Also, your comments on lubrication are great.. I still have the rears open, so I'll add that tomorrow. And yes, I was also afraid of twisting the brake lines so the penetrating shot would have been a good idea... in advance.

Sounds like its the Motors Manual thats confused :confused: I would prefer a regular Chevrolet shop manual for information.If you can borrow one from between 1936 and 1950 the brake overhauling steps are clearly shown and described.

The wheel cylinder centers the shoes on the top.Its bolted to the backing plate and no provision for adjustment.The lower anchor point is the large pin that goes thru the links and is also non-adjustable.The only thing thats "adjustable" is the hand brake lever anchor bolt that connects the flat lever to the rear shoe.This bolt has an eccentric to adjust the clearance between the flat lever and the link that runs between the two shoes.Could this be the centering bolt that they are refering to?Its just for hand brake adjustment.

The mechanical Huck brakes used on the 1934-35 had a centering bolt-which was important to adjust to insure equal shoe contact-but with hydraulic brakes the hydraulic pressure will compensate for any minor differences in adjustment etc.

When you get the rear shoes all installed the next problem will be-The drum will not fit over the new linings.Besure that the hand brake cables are fully released and their adjustment backed off.Also that the eccentric bolt is adjusted to give the shoes the most clearance.Often the newer shoes have a little thicker linings (original linings was 3/16")and you will need to have all the help that you can get to have the drum fit over the shoes.

Yes, the bolt is where the parking brake lever attaches to the rear shoe. And now that you mention it, I forgot to tighten the locking nut tonight before I put the hub back on it. oops... :(

Surprisingly I was also not looking forward to putting the hubs back on, but both of the rears went on with no problem at all. I adjusted both of the wheel cylinder sprokets and got each to drag then backed off 4 clicks. :cool2:

Tuesday I'll be able to bleed the brakes. I installed new bleeder screws with built-in check values. Hopefully they'll work as advertised. I noticed that they had some "stuff" on the threads which made them a little tight to install. I guess that I'll find out that it's some sort of sealer and not a thread size the makes it tough to install.

Thanks for the comments, you solved my eccentric bolt mystery. And since the rears went so good, I'm gonna lower the car and give it a test drive bfore I start on the fronts... also, beacuse I want to turn the car around so that the front end is closer to my workbench!

Billy, I hope you have good luck with your brake job, I reckon you don't need another door in the back of your shop, I know one guy that made himself a new rear door when he went out to test his new brake job and didn't have enough peddle to stop when he came back in from his test ride, he forgot you could "pump" the old manual juice brakes.

Yes, I surely had to pump these too!!

I finished the rears, and took it out for a test spin. works great, but I'm getting some pulling to the right.... I'm assuming that it's the front brakes doing that.

Next week I'll try to jack it up again and pull the front rims. Also would like to check the knee action shocks.

Does anybody have any comments on how I should check them... or where I can look for more information? :confused:

And where can I get a Chev Shop Manual for this year? Does TFS sell them?

You don't have knee action "shocks" but enclosed knee action with "built in" shocks.The shock valves are inside the two little round cylinders bolted unto the front of the housing.If the fluid level is below the shocks the front end will be very "soft". If you bounce it by the front bumper with the shocks "working" it should not rebound more than once when you stop.There is a square filler plug on the upper front of the housing-it sits at a 45deg.angle.Should be filled to that level.I use ATF ,its cheap, or hydraulic jack oil can be used also.Each knee action unit holds about 2 qts.The fluid lubricates the internals as well as enables the hydraulic shocks to function.Do not fill the knees until after you do the brakes.They commonly will leak when the car is jacked up and the suspension hanging down.The packing nuts may be tightened to prevent or slow down the leaking.This is if the knees are not too badly worn and any of the packing is remaining.There is a large packing nut where the big arm enters the housing.It has a small set screw the must be loosened first.Use a large pipe wrench or chain wrench to tighten.Set screw (there-I said it twice) may be in any position around the circumference of the nut.May be buried under grease or dirt.

TFS has a shop manual for 1938-#DG-33 for $20.00.

Thanks Chev Nut... I'll let you know what I find out... and... yes, there is a LOT of caked grease and dirt around the nuts and screws under there...

The above reply was assuming that the car is a Master DeLuxe with knee action.If a Master with a straight axle and leaf springs it has "shock absorbers".They would be single action Delco shocks.The fluid level can also be checked on these by removing the small square plug.Fill to opening with hydraulic jack oil.

Bill, When you redid the brakes on your '31 did you get your help from the 1931 Chevrolet's Shop Manual like I just asked about on "General Discussions" and did you put in all new front wheel and rear axle seals? I plan on doing that with mine and wonder if the Shop Manual explains the quite clearly? Thanks.

No, surprisingly I don't have a Shop Manual for the '31. Actually have never seen one for sale.

I used a 31-36 Repair Manual when I did mine. That had enough info. Also use the Owners Manual. That has the good info about re-centering your brakes.

There is an excellent article on '34-'38 front knee action suspension at www.antiqueautoarchive.com under the restoration section. This info will give you a very complete understanding of how these suspensions operate and how to work on them. Lots of photos also.

Progress check:

I've got the front brakes off. Didn't like the looks of the brake hoses, so I ordered a new set. Meanwhile cleaned the backing plates and all of the other parts.

Also, chipped off lots of dirt with my good buddy Helgy! (He came to my house to cut firewood, and ended up scraping crud off my rims!! What a pal.) We found these weird little square screws. Didn't know what they were for, so I decided to re-read this thread. Hey!!!

Now I know what they're for. Cool. Tighten the packing glands!?!?!? Wow... what an advanced concept. I can't wait to get these babies back together and give it a test on the down-hill from my house.

One question??? I don't know what kind of fluid is in my shocks --- therefore I'll assume jack fluid. (Everything on my car is original and largely untouched since the late sixties or early seventies.)

Can I just add ATF to this? or should I try to pull some fluid out (by a suction hose) and compare it. ??? Suggestions??? Or is it okay to mix fluid types?

The square screws are lock or set screws that prevent the packing nut (large nut ) from turning.

Fluid.If it were mine and the units were completely empty-ie such as new, I would use ATF.reason-cheaper and is of the same viscosity as shock fluid.--If topping off I would select hydralic jack oil--reason--if they still have shock fluid in them its is more comparable.Up until 20 years ago the Permatex brand of jack oil had the instructions on it for filling Delco shocks and knee-action units.If you go to a farm or tractor supply store you can buy it by the quart for a decent price.If it leaks some #30 hydralic oil can be used (used in hyd. systems in tractors etc>).It will be a little heaiver than jack oil.This could cause the shock absorbers to be a little "stiffer" in cold weather.The original fluid was very light so they would not stiffen up in cold weather(shock valeving).Actually any oil product will be OK as lubrication is not the main concern.Some people even filled them with #90 or #140 gear oil when they leaked.This would result in a very firm tide though.

Okay, thanks.

First some pictures... and then another question!

and three more.....

Okay, now for the question... regarding bleeding.

Disconnected the brake lines and used a MightyMite to "suck" the fluid until it was clear. (Initially it looked like Coca Cola and had little rust flakes in it.)

Then reconnected the lines and "sucked" the fluid through the wheel cylinder relief valve. Got air bubbles and fluid.

Did this to both front wheels. But the brake pedal still doesn't hold any pressure.

So... there must still be air in the lines? Right?

Or air in either of the new wheel cylinders? Right?

I've lowered the car and it's on the ground now, but the peddle goes straight to the floor. Almost had a new opening in the garage! ha! (You were right MrMack!).

Any idea on how I should proceed? or just in order - eg. Left Rear, Left Front, Right Rear, Right Front -- like the book says to do? And bleed it again?

Bill, you didn't indicate that you bled the rear brakes. The brake system on your car is autonomous and must be treated as one unit. You have the right idea of starting with the furthermost wheel and working up to the one nearest to the master cylinder. You must insure that the master cylinder is full of fluid at all times during the bleeding procedure.

Yes, Billy also before you do any serious bleeding, it is a good idea to have the shoe to drum clearance adjusted correctly , with the wheel and tire on the spindle. You didn't mention whether you had the drums turned or checked for specs. With the brakes adjusted bleeding and filling the reservoir must be done untill there is no air in the system. be careful when you use your MityVac as air can be sucked around the plastic tubing and looking like it is coming out of the cylnder. after a brake job is done the brakes should be adjusted after a normal trip of 100 miles or so. After you get the initial adjustment done, test drive and get up to speed and do several brake to stops, gently then harder as the shoes get worn in, there will be some pulling to the side and some squeeling until everything gets worn in to fit,just keep on adjusting, and driving, the bad thing is about when everything gets to fitting well it is worn out! Ha!

Bill..
I think anyone who has restored a '30s or '40s Chevrolet has had to do the brakes. The brakes was the first thing I did on my '41. I had the normal difficulty with installation, adjusting, bleeding, etc. I installed all new cylinders, hoses, shoes etc. After everything was done on the wheels I tried out my new brakes.The right front wheel would lock up immediately when I applied the brake pedal. I completley redid that wheel many times. I could take it all off and put it back together blindfolded.
After all this someone mentioned the master cylinder.
I removed the master cylinder to rebuild. The problem was one of the two small holes inside the cylinder was rusted closed. Completely blocked. I drilled out the hole, rebuilt the master cylinder and "eureka " problem solved.
Don't forget the master cylinder. Rebuild it while you are doing the brakes. You won't regret it. The two small holes let the fluid in and out of the resivoir.
Good luck JIM

JIM, I agree, any restoration of a car or truck specially one that has not run and been driven for several years requires a complete brake system rebuild all the way, I have been fortunate in that I have been able to turn the drums, (on both the 53 and 51 just enough to true them up.) I got some chatter from the lathe cutter until I put the screendoor springs back on the drums and also used an elsatic wrap on the drums during turning, it appears that the older model drums are much more flexible than the newer drums.
I also was able to rebuild the master cylinder, with minor honeing and running a small drill bit in those small holes you mentioned . One thing I did was bush up the clutch and brake peddle mounting shaft, and removed the 1/8" plug from the shaft mount and replace it with a zerk connection and be able to grease that device.

All good comments... I'll let you know what I find this weekend.

For the record, I did rebuild the master cylinder when I first bought the car. The brakes wouldn't free up -- yes the little hole was very plugged.

And yes, I bled the rears.. just didn't mention it, because I was trying to shorten my note.

And finally, I adjusted the brakes by spinning the drums before I started bleeding.

See you later! Again, thanks!

Boy, oh boy, did I ever learn a lot THIS weekend. My 'ol buddy, Helgy, came by on Friday and we spent about 4 hours bleeding the brakes. Originally had to pump the peddle about 5 or 6 times in order to get it to hold. After going around the wheels two complete times it still took 3 pumps to get it to show any firmness. Not good.

So, remember that I bled them myself using a "suction" device and still couldn't get them above the floor without rigorous pumping. So, the general feeling is that there was still air somewhere in the dang system!!

Now, Helgy, and I did one thing right away. We ONLY used the "pressurized" method of bleeding instead of the "suction" method. With two people, one can pump and stand on the brakes thereby keeping the system fully pressurized.

FIRST THING that I found was the bleeder valves seems to be "slightly" reacting to the pumping strokes. I could just barely see the fluid in the tip of the value pulsating with each pump... Now these were the $6 valves with a check valve built in. Suppose to allow a lone person to bleed the brakes and it prevents air from coming back in.... but.... I didn't like the slight pulsating that I saw.

So we replaced all 4 values with original style ones. Then went around the horn again and bled each wheel... this time let lots and lots of fluid come out. At the end, the peddle only required 2 or 3 pumps to be firm.... STILL NOT GOOD ENOUGH.

FINAL ACT -- While bleeding the very last wheel, something nasty happened!!! Helgy pumped and I just began to open the last valve, but then a hissing sound occurred... WHEN A TINY PINHOLE SPRUNG A LEAK IN THE LINE THAT CROSSES THE REAR AXLE. FLUID SPRAYED OUT EVERYWHERE!!!

So, now I an on hold again, waiting for a brake line kit to arrive from the Filling Station.

CONCLUSION -- It is better to apply pressure than vacuum to the system when bleeding. I would never have found the pinhole leak with the MightyVac method of sucking at each valve. But with Helgy standing on the peddle and applying the force of his full 115 pounds, the entire brake system was tested for INTEGRITY instead of just moving fluid by vacuum... I's sure glad that this happened in my garage and not on the freeway offramp!! Thanks Helgy.

Billy I had some of the same experiance yesterday getting the 53 ready for a tour, Mity Vaced, and mity vaced, not much came out ,so I filled master cylinder loosened the bleeder on rt rear wheel , pumped five times hard refilled MS and went back to mity vac, I had enough crud in the line that wouldn't vac out, I was by myself so I repeated. hooked up Mity Vac and filled master cylinder pumped 5 times got about 3/4 a bottle of dirty fluid then when it cleaned up used (used about a pint of new fluid) the mity Vac and now have a good full peddle, Had to adjust each wheel about three clicks on average.

The replacement brake lines arrived 8 days after ordering them. They look great!!

But... boy are the old ones a bugger to get off! Ouch... Had to take the two rear pieces off still connected together.

Here's my question: Does anyone make the brass tees for these? I had to really torque to get the lines off and I was afraid of breaking one of the three-way tees.

Billy, I know that Nationalchevyassoc makes them for 49-54 chevy cars, maybe they are the same. I assume you mean where the two rear lines hook together and the hose to the rear metal line hooks together.

Bill
I have found that using mityvac at wheels is not successful. Much better to have friend push brake pedal while you open bleed nipple then close nipple then release pedal. Also friend can top up master cylinder as fluid level drops.

TonyW, I found that a mityvac works ok, if not to perfection, with new rust free lines and good clean Dot 3 fluid, fill the master cylinder with your Mity Vac hooked up, pump out about a half a bottle of fluid, refill the master cylinder, pull a vacuum, crack the bleeder valve with a 3/8" inch thin boxend wrench that you place on the bleeder valve before attaching the Mity-vac hose.

I have thought about fabricating a pressure bleeder that screws into the top of the master cylinder with a quart reservoir for fluid and then pressureizeing it with a airline from the shop compressor...Do any of you have experiance with the one shown in the Chevrolet Shop Manuals?

I have a problem of finding that friend whenever I need one. I agree there isn't a good replacement for a human helper. I guess that was what God saw when Adam was alone in The Garden of Eden. of course that was also before Bra burning and NOW, and community property 401K's!!!!

I also have had good luck with the Mityvac.Good air tight connections are important -or is that vacuum (no air) tight.Prevents brake fluid from spilling on wheel etc.-removing paint.Also the color can be observed so you know when the "oldstuff" is drawn out of the line.

Bill - I've adjusted,rebuilt and bled the brakes on my 40 Chev many times since 1963. Here's what works for me. When I replace the linings, I adjust each shoe out until it is tight against the drum (wheel won't turn) then back it off until the wheel turns with a whisper from the drum drag. Softness in the brake pedal but some pedal indicates air in the system. Softness and pumping to get pedal indicates both air an lack of adjustment. To bleed the brakes requires 2 people. One on the pedal and the other to get brake fluid all over him. Over the years I have tried all kinds of gadgets to help bleed the brakes and none have worked as well as the fluid on the floor method. I do it just as you mentioned. LR, RR, RF, & LF. When I completely rebuilt the system, I refill it with fluid befor bleeding it I pump the pedal as hard as I 30 or 40 times. This seems to assist in forcing the air out to the wheel cylinders. Check the fluid a couple of times while doing this. Before I open the bleed valve each time I have the pedal person (usually my wife) long stroke the pedal 5 or 6 times before she holds it down and I open and close the bleed valve. I bleed each wheel until I see or hear air coming out of the bleed valve and then have a solid stream of fluid. I very seldom get much pedal until the last wheel is bled (left front). Just a slight amount of air will let the pedal go all the way to the floor. If air has been introduced into the system you will usually get some air from each wheel cylinder. Every time I've given up on a wheel and quit bleeding because I thought there was not any air I've had to go back and bleed it until I did get air out. Good Luck, Mike Deeter

Gee thanks everyone... It seems that after all these years, it still takes two to tango.

Will let you know how it goes now... by the way, when I removed the master cylinder, I noticed that some of the wiriing is frayed and has some bare strands showing... first saw it around the stoplight switch, but also could see bare wires going up to the headlight dimmer switch. How much effort should I spend on THAT?

While you are there FIX what is bad!

Billy
Pressure bleeder from master cylinder is the easiest way then comes the offsider. I have also successfully bled brakes by fitting a hose to the nipple and ensuring it is raised above the it opening the nipple and quickly pumping the pedal several times myself.
Using the mityvac draws air past the nipple threads giving false indication.
I also agree with the stainless sleeve in the master cylinder, next time you need to rebuild it you will only need get the rubber parts.
Tony

FINAL REPORT

All is done. Helgy and I finished the job today! Bled all of the brakes using the "two man" method. Also shortened the hose to about 12" so that I could keep it full of liquid all of the time and not have air move back to the bledder valve.

Got all four wheels done and the pedal would only come up about an inch off the floor... dang!!! What was wrong? Was there air in the new wheel cylinders? In the New Master cylinder? in the new lines?

Helgy said, "why don't we go around and adjust all of the shoes again?" -- not something that I was real eager to do, since we hadn't done any driving since I installed the shoes and adjusted them. But we decided to do it anyways.

Got the first rear done... tightened it about 15 clicks and backed off 4 --- did this to both the front and rear adjustments on each cylinder. Then the other rear, same number, tighten 15, loosen 4.

Checked the pedal --- no change... still one inch off the floor.

Then went to the left front. Tightened 12, backed off 4 clicks... arghhh! Not much difference, but it was becoming apparent that I had been too easy on my initial adjustment.

Started the final wheel, the right front. Tightened the forward cap 30 clicks... Helgy asked "Are you going the right direction?"... yep, I was.... went another 25 clicks before the shoe began to drag!!! :eek: Finally, ended with 60 tightening clicks and backed off 4.

Helge jumped in and pushed the pedal and exclaimed... "We've got LOTS of pedal now!!!"

Rolled the car out, took it up the hill from my house. Coming back down the hill, I purposely locked up the tires, skidded rubber and the steering wheel never flinched either direction!!! Cool!!! :cool2:

So, now I'm done. After 3+ years, I have my car on the road with really good brakes!!! And I'm a little smarter, too. I know that if you bleed the lines and don't get any air, then you need to adjust the shoes and close up the gap, no matter how close you THINK they already are!!! Sure is great to have someone else around to help you break through your mental barriers!!!!

Thanks Helgy!!!

Thank you all for this great site. I replaced all my wheel cylinders last night, flushed and had great breaks.

Thank you again.

mark