Lost My Brakes . . . Sorta'

[grey beard]

Renewed my brakes back a year or three, and replaced every part. Period. New flex and steel lines. New cylinders, shoes, etc. Dot 5 whoa juice.

Well do I remember the struggle to get the machined drums to go on the new shoes. They just seemed too dang big. Finally scuffed a scotch or two off the leding edge of each rear axle shoe, then the drums went on. Almost seemed like the shoes were oversized, or needed to be arc ground.

I adjusted all the new brakes in the usual fashion. After they were bled, I had beautifully high pedal - the envy of any MoPar nut.

Now I've driven this truck maybe 75 miles. Last trip out, lost my brakes. I mean, went for the whoa button and nobody was home. Pumped them and they came right up, and I stopped okay.

Got back to the barn and first thing I chcked was the master cylinder fluid level, which was down just a tad. Topped it off and crawled underneath. No leaks, no drips, nothing amiss. Sooooooo, while it was jacked up, I readjusted all the brakes. Some adjusters took a lot of slack up. When I was done adjusting, I had normal brake pedal once again.

This seems unusual to me. I realize that newer stuff all has self adjusting brakes and that our Pilothouse trucks do not have this feature, but it seems unusual to me that these brakes needed adjustment so soon.

Any thoughts or experiences with this issue?

Thanks

[Norm's Coupe]

Could it be a bad MC? I had a MC go bad on me all of a sudden while stopped at a light. Brakes were fine when I stopped, then the pedal just went to the floor while sitting there. Pumped it a few times and the pedal came up again, but then slowly went down again. That was on a more modern car though, but don't remember which car it was that it happened in.

Don't remember what my book says for my coupe about adjusting the brakes, but it seems like it was a pretty regular schedule that they recommended.

[TodFitch]

They do need regular adjustment but I'd guess I go about 2000 to 3000 miles between checking/twiddling with the minor adjustment. Maybe 10000 on the major adjustment.

So 75 miles sounds awfully short distance. Like Norm, I'd suspect the master cylinder. But you might want to check to be sure that the adjustments on the wheels are staying where you put them (maybe a loose nut on the major adjustment cams/shoe pivots).

[Jerry Roberts]

One easy check I used to do on master cylinders was ; Very ,very slowly apply pressure to your brake pedal , if your master cylinder is leaking the pedal will go to the floor .

[MBF]

GB-just a guess, but since you said they were really tight its possible that one of the concentric adjustments backed off bringing the shoe closer in at the bottom requiring the top to travel further out than they normally do. I'm also wondering if your master cylinder plunger got hung up in the down position. Another possibility is that one of the shoe tabs wasn't seated all the way in the cylinder slot which may have been causing the tightmess. Was there ever any DOT3 in that system since the rebuild? Just guesses-I had to adjust mind this weekend too-lots of pedal just no stop! Mike

[grey beard]

Nope, always only dot 5 in this system from brand splinter new. What I found when i started readjusting was that all the shoes were pretty far out of adjustment. No one shoe or adjuster was out, the whole bunch was out og adjustment. Hardly and mileage, and here it acts like it's been around the world.

[they_call_me_tred]

whoa! what the hell happened this weekend!!!

i took my girl out to freemont street here in vegas and on the drive home at a stop light my driver's side wheel cylinders **** the bed and just locked up that wheel.

i pumped the pedal a few times hoping for anything short of a ride home in the cab of a tow truck and it let up a little, but i had to drive 20 miles home with the front brakes on a bit. man, you should have seen all the brake dust when i pulled that drum off!

my question is this, with a stock front brake setup, should i be using dot 5 fluid or 3? it never occured to me to use 5...

oh, and i found the assembled wheel cylinders in stock at napa, and based on the price, they are made in america, not chi chi chi china.

thank you, sorry to hijack the thread.

[TodFitch]

whoa! what the hell happened this weekend!!!

i took my girl out to freemont street here in vegas and on the drive home at a stop light my driver's side wheel cylinders **** the bed and just locked up that wheel.

i pumped the pedal a few times hoping for anything short of a ride home in the cab of a tow truck and it let up a little, but i had to drive 20 miles home with the front brakes on a bit. man, you should have seen all the brake dust when i pulled that drum off!

my question is this, with a stock front brake setup, should i be using dot 5 fluid or 3? it never occured to me to use 5...

oh, and i found the assembled wheel cylinders in stock at napa, and based on the price, they are made in america, not chi chi chi china.

thank you, sorry to hijack the thread.

A bad brake hose has been rumored to cause a single wheel to lock up.

If all wheels are locking, look to see if the rod that connects the brake pedal to the master cylinder is adjusted too long or if the relief port in the master cylinder is blocked up.

I have had no problems with DOT5 in my 1933. However I would not advise mixing types of brake fluid, it seems that everyone who has had problems had a mix. The successful conversions to DOT5 that I am aware of used all new and or totally rebuilt components including all metal tubing.

[Norm's Coupe]

whoa! what the hell happened this weekend!!!

i took my girl out to freemont street here in vegas and on the drive home at a stop light my driver's side wheel cylinders **** the bed and just locked up that wheel.

i pumped the pedal a few times hoping for anything short of a ride home in the cab of a tow truck and it let up a little, but i had to drive 20 miles home with the front brakes on a bit. man, you should have seen all the brake dust when i pulled that drum off!

my question is this, with a stock front brake setup, should i be using dot 5 fluid or 3? it never occured to me to use 5...

oh, and i found the assembled wheel cylinders in stock at napa, and based on the price, they are made in america, not chi chi chi china.

thank you, sorry to hijack the thread.

I can remember that happening to a lot of people back in the day when these cars were newer. Usually it was a problem of the brakes not bleed properly and air would build up in the system. You would see people go to the wheel that was locked up, loosen the bleeder screw to let the air out. That would release the locked brake so they could get home and fix it, or take it in for repair.

[Norm's Coupe]

Nope, always only dot 5 in this system from brand splinter new. What I found when i started readjusting was that all the shoes were pretty far out of adjustment. No one shoe or adjuster was out, the whole bunch was out og adjustment. Hardly and mileage, and here it acts like it's been around the world.

When you fixed the brakes originally, did you put new oil light washers soaked in oil under the steel washer on the pivot pins? Or, felt washers soaked in oil under them? If not, the shoes could have stuck close enough to the drums to wear the shoe down fast. I can't think of anything else to cause all of them to be out of adjustment like that. It's unlikely you would have all bad return springs. Or, as mentioned the MC could have stuck and not allowed the shoes to return properly, again wearing the brake shoes faster and causing them to get out of adjustment all at once.

[Don Coatney]

Dave;

What is your procedure for adjusting your brakes? Do you use the Ammco tool or its equivlent?

[grey beard]

Don,

When I rebuilt the brakes, everything was new. I do not have an Aamco gauge or its equivalent, but I was able to get the shoes centered using feeler gauges and the drum. It is also possible to assemble the shoes and leave the anchors loose, then tighten the adjustments and center everything inside the drom before you tighten the anchors. This is the procedure outlined in an old Motors Manual.

Anyhow, on my first few road tests, brakes were fine. After a few hundred miles I had to pump to get pedal and whoa power. Just readjusting all the minor eccentric adjusters cured the problem. Mebby sometime soon I aught to do the full readjustment schmear all over again from the beginning.

Took the grandkids out for ice cream last night - which is what Pilothouse trucks are REALLY made for, and the brakes seem fine.

[desoto1939]

This is what I have learned over the years from my 39 Desoto that has the 1 brake cyclinder on each wheel with the eccentrics. I have both the Ammco brake gage and also the Miller MT19 tool with all of the sleeves (7) to fit the various cars and smaller trucks.

I have done a lecture for the AACA at the Phila delphia Convention this past Winter in Feb. After doing the brake job with either tool this just get the shoes arched in the proper setup for your drums. You still need to do a minor brake adjustment to really get the good pedal that we want. As per other discussions since we now almost always have power disc brakes on our cars we have forgotten that the older cars did have a softer pedal especially since there was not powere and also because there is a single line to supply the fluid to the cylinders.

If you just do the major brake without the minot brake adjust you will still have a soft pedal.

Keep the brakes adjusted every 1000 miles. Also with Dot 5 synthic fluid you need to completely flush the MC and all lines with denatured alcohol. This needs to be done several times prior to putting in the dot 5. I bleed mine at least three times and on the last time the lines then were clear of the old fluid. When the dot 3 mixes with the dot 5 you will see the seperation of the two fluid in the catch jar.

write to me if you need the ammco brake gage. I live near Valley Forge PA.

rich hartung

desoto1939@aol.com

[TodFitch]

...snip... Also with Dot 5 synthic fluid you need to completely flush the MC and all lines with denatured alcohol. This needs to be done several times prior to putting in the dot 5. ...snip...

rich hartung

desoto1939@aol.com

I have heard that the problem with brake rubber failing after switching to DOT5 can be because of using alcohol to clean the system: The claim was that the alcohol damages the rubber.

No personal experience on swapping fluid types as I replaced all components in my brake system including all the metal tubing when I switched to DOT5. And, about 12 years on, I have had no problems.

[Don Coatney]

Don,

When I rebuilt the brakes, everything was new. I do not have an Aamco gauge or its equivalent,

Anyhow, on my first few road tests, brakes were fine. After a few hundred miles I had to pump to get pedal and whoa power. .

Dave;

It is my opinion that the touchy feeler gage adjustments dont work. The only way to correctly adjust brakes is use of the proper tool or an equivlent. But that is my opinion.

However when you say you had to pump to get pedal tells me you have air in the system. Pumping the pedal will not correct faulty adjustment but it will correct air in the system. Make sure you do not have a leak that introduces air into the system. Bleed them again and see what happens.