treadlevac woes..

so here is the jist....

1956 cadillac, rebuilt treadlevac, checked it holds pressure, new wheel cylinders, new brake shoes, new springs, retainers, rubber lines, and adjusters. the shoes are adjusted appropriatly.

Bleed the brakes... soft pedal, pedal to the floor and it barely holds the car at idle....

treadlevac checkvalve in the resevoir opens and closes as the pedal is pushed and released..

Blead the brakes numerous times with the same results...

ANY HELP?

 

Throw it away and get a Master Power booster...

R-

 

so does anyone have any other input...

 

I did what 40StudeDude suggests on my '59 Lincoln. The Treadlevac is not a safe braking setup. One of the small "street rod" style vacuum boosters is the same diameter and will fit well in place of the stock unit.

 

so anyone have any suggestions besides taking it off and throwing it away?

 

did you put a plug in the out going port, to see if it is rock hard?

 

Take it off and use it as a door stop?

 

yes and it is, no leaks anywhere.... just cannot get the stiff... clamped the lines off one at a time and still cannot get it right....

 

the brakes have to be out of adjustment. crank the adjusters tight as you can to lock the wheels solid and see if you have a pedal.

 

the adjusters are all the way out and rubbing the shoes on the drum now.

 

Did you rebuild the Treadlevac? One of the main reasons those things are dangerous is that they leak internally, where you can't see it.

Never mind, I just saw that you rebuilt the unit.

If the pedal was hard with the output port plugged, then it's a problem on the way to or at the wheels. It sounds like you must still have air in the lines.

 

Do you have a brake switch on that setup, the kind that is a hydraulic switch, like my Lincoln? If so it might be taking air from there. I have one on my Lincoln and have had absolutely no issues at all. All I did was rebuild the master cylinder and put a new leather seal in the vacuum unit. Nice firm pedal.

If you have a firm pedal without the brake line connected, that means your issues are somewhere else in the brake system. Did u by any chance remove the hoses from the wheel cylinders, then put them back using the old copper washers. If so your problem is probably there.

That treadlevac unit isn't any worse than my Chrysler Vacu-ease unit. Mine (on my 54 Chrysler) blew the seal and started sucking brake fluid right into the intake manifold.

You are bleeding the brakes with the engine off, correct?

 

they may be rubbing, but not all the way locked and locked tight. it will tell you whether it is hydraulic or something out of wack in the wheel.

 

hey guys, I just wanted to bump this and maybe get some fresh eyes on it and possibly find some answers.

cookiemonster131 is my brother and I have been working with him off and on trying to help where ever I can to get this solved.

I know that treadlevacs are a pain in the rear but the car in question is a very nice low milage caddy that he would like to keep original as possible so please refrain from making uneccissary negative comments.

If all you have to say is something that is not helpful do all of us a favor and go be a dick to some one else.

we are looking for an answer not Dennis Miller.


d2 willys, the early caddy does not have an inline pressure switch, it instead has a bleeder valve, (I know crazy right? a bleeder on the mc!)

but none the less when the brakes are being bled, it feels like you are starting to get a decent pedel and then it just gives out.

the best way I can describe it is when you tighten a cheaply made nut too much how it feels pretty good then it just strips out...

and the treadlevac has been rebuilt by 2 different treadlevac "experts" that only do old cadillac treadlevacs.

everything is brand new all the way around except for the metal lines but after bleeding the brakes for an hour there is no leaking fluid anywhere.

and tb33anda3rd, we have tried adjusting the drums every way you could imagine to no avail.

I know that no one is exempt from overlooking simple things but this is def not our first rodeo...

I had something similar happen on a 63 beetle one time and it took 2 days of me beating my head against the wall to take it to a 32 year veteran vw mechanic who then spent 8 hours a day for 3 days solid on it before he got any semblance of a pedal...

he felt bad and only charged me $100.

point is, you have a mc/lines/hoses/wc/shoes/drums but sometimes you have magic brakes and that overides conventional wisdom

 

I would follow these steps one by one till something shows up:

Loosen the brake line from the m/c and bleed till only fluid comes out. Then plug the master cylinder and see if the pedal is firm and stays like that with pedal depressed for a minute or so. You say there is a bleeder valve on the master cylinder? Hmmm, never saw one like that. Could you post a pic of this? If you do have a bleeder valve, then plug the m/c and bleed it through the bleeder valve, instead of loosening the line approach.

If pedal is firm the problem lies down the brake system. Take one line off at a time and see if the pedal firms up. This should point you to where the issues are. (I would remove the rear line first (up near the m/c or front brake fittings) and plug the fitting. This would narrow it down to front or rear brakes)

By systematically going through this, the culprit will show up. If I think of anything else I will post.

 

thanks man, the bad part is this is all stuff that has already been done...

just keep trying I guess.

and yeah we plugged of the mc and bled the brakes, the pedal felt better for a second but then went back to where it was...

I appreciate your time all the same

 

I figure this ain't the answer you are looking for, but this worked on my 55 Lincoln for a couple hundred bucks and a couple hours labor... No problems now...

I used the back of the treadle-vac booster to make an adapter, and changed the pedal ratio via repositioning the fulcrum setup already in the car.... easy cheesy...


If the treadle-vac in the car is loosing pedal and not loosing fluid, then the m/c portion of the unit is not right, (yea I know duh). Since it is a displacement unit, the way I am thinking, the seal just about has to be letting fluid get past the "piston". For some reason the rebuild isn't taking..

 

when you plugged off the master cylinder, was the pedal rock hard? would not move a bit, just like it was welded in place?

 

Excellent question, I was just going to ask that too. Eliminate the M/C first. If the pedal sinks with it plugged, go get another m/c.

Those displacement types relied alot on piston bore clearance being in spec.

You might try putting an oil pressure gauge on the m/c output fitting and watch it while you depress the pedal.

 

Did the rebuild include a new piston(shaft)? If that piston has ANY wear, pitting or scoring it will not maintain pressure.

Dan

 

agreed, the kit I bought had no new piston included.
Thinking that the casting may have a void in it. The casting looks like some cheap pot metal was used, which to me means trouble.

Do a pressure check with the gauge and let us know what happens.

 

Since North Carolina is a home base for this problem, Bepco MIGHT be able to help with sleeving, boring, and making new parts for a price,
Bepco is in Raliegh. I have contact/coworker in Charlotte to help with paperwork only and what you might need to spend.
No promises, option.

 

thanks guys! now we sound like we are getting somewhere!

the pedal became more stiff but was by no means rock hard. so I will have to check that out...

and thanks patrick2965, let me know if you hear anything?

 

question?

if I use a oil pressure gauge, what should it read?

pegged out?

 

The casting has nothing to do with holding pressure unless it is cracked or corroded through= leak onto the floor. There are only 3 places for fluid to go on a BTV: 1. the brakes. 2. past the compensator valve. 3. past the shaft seal between the m/c and the vacuum unit.
You know about 1.
Set the unit up on your bench with the cover removed from the reservoir, 1/2 full of fluid. Push the brake rod and watch the compensator valve for leakage. Move the compensator valve pin in the reservoir to try to seat it. Leakage past the shaft seal will show fluid flow from the vent tube that is cast into the housing at the back of the reservoir.If the compensator leaks, replace it. If the vent tube shows fluid, replace the m/c piston. Kanter has both.

Dan

 

thanks dan, will try that!

 

Thanks for the input guys and thanks to Delton for helping me through this ordeal. With the master blocked off it is rock hard pedal. Delton and I are going to hammer on it next weekend so keep the suggestions coming! Thanks a ton guys!


I will get a pic this weekend and post it also.

 

I was thinking that the casting might be cracked and allowing the pressure to build but gradually leak off. The casting area is the main well and the reservoir that I would/ve checked for. If it were cracked here it would leak down, but fill the reservoir back up, therefore no loss of fluid.

But as was mentioned, the m/c sounds fine as it holds pressure.

As for the pressure gauge, I was suggesting to use one for a visual leak down indicator.

Next area is to disconnect rear brake line and block. See if the pedal is hard, and if so, rear brake issue. If not, front brake issue, which needs to be corrected. Then reattach rear brakes and see if pedal is firm, if not then rear brakes are leaking too. Like I said, just because you don't loose fluid doesn't mean the system is pulling air back in on the release of the pedal.

Sure you will find the problem soon. Good luck.

 

here is the pic



looks like Delton and I may have a date with the Caddy Monday... Him or I will update this thread soon! keep the ideas coming!

 

Thanks for the pic. Never saw one with the bleed valve on the end of the MC. Question: How did you plug the MC, with the brass fitting and with the plug at the tube fitting, or without the brass fitting and plug in MC itself? The reasoning: I would think you would need copper washers on both sides of the brass fitting. Doesn't look like either side has them.