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Username Post: Bleed Treadle Vac        (Topic#340359)
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-03-16 03:31 PM - Post#2659819    

I just received my rebuilt Treadle Vac and am having a very difficult time successfully bleeding the system.

I am 100% confident that all the air is out. I am pushing clean fluid out of each wheel cylinder.

I have read that bleed left rear, right rear, right front, left front.

I also read that the treadle vac needs to be level to bleed it? So do I jack up the car?

Not sure what I am doing wrong. Any help? Thanks



Edited by benbuilder on 11-03-16 03:48 PM. Reason for edit: No reason given.

 


Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
11-03-16 06:43 PM - Post#2659842    
    In response to benbuilder

I always recommend tilting the front of the T-Vac up a bit when bench bleeding it. Air can get trapped in the front of the MC. Then install it and bleed the foundation brakes in the sequence you mentioned. On the bench and on the car, push the vacuum piston only about halfway during bleeding.

Jalapeno


Edited by Jalapeno on 11-03-16 06:45 PM. Reason for edit: No reason given.

 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-04-16 01:04 AM - Post#2659867    
    In response to Jalapeno

Jalapeno,
I just found this other post from you.

"I find bench bleeding a Treadle-Vac, nose pointed slightly down, does a better job than on the car. After installation, bleed left rear, right rear, right front, left front. The pedal should not go all the way to the floor after bleeding. It is crucial that the pedal return all the way while bleeding, as the last fraction of an inch of travel is what replenishes the pressure side of the system from the reservoir. Keep the MC full during bleeding, check it frequently, don't let it run low enough to suck air into the pressure side of the system."


I will try again today. I have bled these brakes 4 times and I am at the wheel cylinder position. So I can see the clear tube with no air bubbles. I hope the tipping of the master is the solution. I am going to jack up the rear as someone else suggested. Thanks for the help.



 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
11-04-16 05:32 PM - Post#2659962    
    In response to benbuilder

Oops, yes, I meant DOWN and not UP, my mistake, glad you caught that.

Jalapeno


 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-05-16 12:12 AM - Post#2659975    
    In response to Jalapeno

Well, no luck. I have tried bench bleeding, bleeding in the car, car jacked, everything. I have bled cars before. I called the rebuilder, he suggested adjusting the brake pads out to almost grab. Still nothing. He suggested sending it back. I removed it last night. Frustrating.

I guess this is part of old car restoration.

Thanks for the help.



 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
11-05-16 10:55 AM - Post#2660039    
    In response to benbuilder

Sorry for all your problems.

What exactly are you experiencing that tells you it's not bled properly? As you mentioned, there are no air bubbles at each wheel cylinder, so it isn't that.

Soft pedal? Pedal going to the floor? Too hard a pedal?

Jalapeno


 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-06-16 10:19 AM - Post#2660159    
    In response to Jalapeno

The pedal goes to the floor. It feels ok, not great, but ok after I bleed the brakes. One minute later the pedal will go to the floor when I apply pressure. No air at all in the lines. New wheel cylinders, brake lines and hoses. No fluid dripping anywhere. Thanks for the help. Its frustrating.



 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
11-07-16 02:11 PM - Post#2660412    
    In response to benbuilder

Maybe the MC is leaking into the booster? Or maybe it's leaking past the tipper valve (in the bottom of the reservoir) or past the seal around the nut that holds the tipper valve, from the pressure side of the system into the reservoir itself.

If you are using DOT 5 (silicone) fluid, you really have to tighten the fittings. Regardless of the fluid, always use line wrenches on every single connection. Sometimes you can get a "reverse leak" (my term), whereby the fitting is tight enough to not leak fluid out but loose enough to let air in. Since a liquid is thicker than a gas, it is physically possible, and I have personally encountered this condition a couple times. So crank down all those fittings with line wrenches.

Jalapeno


Edited by Jalapeno on 11-07-16 02:12 PM. Reason for edit: No reason given.

 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-08-16 01:28 AM - Post#2660529    
    In response to Jalapeno

Jalapeno,

Thanks. I called the rebuilder yesterday and did some visual checks. I bench bled it again. I am going to install it again today and do one other test. He wants me to test with vacuum connected but no brake lines. I will report back. I was curious about the leaks as well. I see none. I will retighten all and try again.

Thanks again



 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-15-16 01:24 AM - Post#2661662    
    In response to benbuilder

I re bled the treadle vac. I installed it and tested it without any brake lines as requested by the rebuilder. I installed a plug where the line would go out. I had hydraulic lock with the car running. Treadle vac is good.

I then bled the system and the pedal goes to the floor when started. I then isolated the system so the front brakes only were connected. I plugged the line to the rear brakes. I had good brakes at this point. So the problem seems to be to the rear brakes.

I plugged the pass rear brakes at the rear distribution block and had good brakes at the pedal with the car running.

I am now investigating what is wrong with pass rear. I cant imagine what it could be. Its a new short line with a new wheel cylinder.



 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
11-15-16 06:19 PM - Post#2661778    
    In response to benbuilder

Your step by step procedure should become a sticky. Post what you find with that pass rear wheel cylinder and line.

Jalapeno


 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
11-25-16 02:29 PM - Post#2663107    
    In response to Jalapeno

I finally had some time to complete the brake bleeding. I decided that because the problem was isolated in the passenger rear, I needed to make a change. I remembered that I bought a new rear brake hose, but not a new distribution block (tee). I changed the distribution block and rebled the brakes as originally directed and it worked out fine. Long process, but I determined that the hose must not have been compatible with the block, or the block was bad. I don't know.

Thanks for all the help.

Jalapeno, I am not sure how to make a sticky, If I am directed, I can do it. Otherwise someone else can take my info and do what they wish.



Edited by bowtieollie on 12-23-16 05:58 AM. Reason for edit: No reason given.

 
bowtieollie 
ChevyTalk Subject Matter Expert
Posts: 21220
bowtieollie
Loc: See the USA in your Chevr...
Reg: 12-06-99
12-23-16 05:59 AM - Post#2667431    
    In response to benbuilder

This was an informative thread.... it is now sticky.

Merry Christmas!

Yooooo Jaly, I just rebuilt the Tredlevac you built for me 16 years ago..... time flies... now converted to DOT 5. You can guess why.

Bowtieollie
Chevytalk.com Moderator


 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
12-23-16 08:01 PM - Post#2667595    
    In response to bowtieollie

Ollie, that's a long time for a T-Vac with DOT 3 in it. Glad you made the conversion to DOT 5. I've had DOT 5 in my T-Vac for over 17 years. I topped off the fluid in it one time, about 7 years ago. It still works great.

Jalapeno


 
Hugomiller 
"3rd Year" Silver Supporting Member
Posts: 125
Hugomiller
Age: 68
Loc: Florida and UK
Reg: 05-02-17
05-02-17 09:09 PM - Post#2689391    
    In response to benbuilder

I would try clamping a pair of vice grips on each brake hose in turn & see what the pedal feels like. It might isolate the problem area.



 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
05-14-17 01:12 AM - Post#2691164    
    In response to Hugomiller

I finally got the impala ready enough for an inspection. I drove the car for an inspection-1/2 mile away. All was fine. Passed.

I drove the car for another 3 miles and the brakes were fine. Then they slowly started to become spongey. I drove the car home and parked it. I did not see any fluid dripping anywhere. Treadle vac was full.

This morning I went to the car and applied the brakes (not started). I have a Hard brake pedal. Once I start the car the pedal srops a bit. When I put it in reverse, it drops a bit more. When I shut it off and pump the brakes a few times, the pedal is right where it should be in terms of position and stiffness.

Any suggestions? I like the idea of vise grips on the hoses to isolate the problem.

I thought I had this figured out. I drove this car around the yard and in and out of the garage after I had had the treadle vac rebuilt last fall.



 
Jalapeno 
Senior Member
Posts: 9818
Jalapeno
Loc: The Republic of Texas
Reg: 04-30-00
05-15-17 11:59 AM - Post#2691433    
    In response to benbuilder

Did you look inside the booster to see if fluid was in there? Not sure what else to tell you.

Jalapeno


 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
05-17-17 01:04 PM - Post#2691686    
    In response to Jalapeno

Thanks. I have fluid. I called the rebuilder and he thinks a compensator is bad. He is going to walk me through the removal and reinstallation of a new one. I will get back with a report.



 
benbuilder 
Forum Newbie
Posts: 92

Reg: 12-06-15
06-03-17 12:55 AM - Post#2694095    
    In response to benbuilder

I am going to answer my own question. I readjusted the brakes and all seems fine. They were not out far enough. Thanks for all the help.



 
Notodden_56 
Forum Newbie
Posts: 4

Reg: 03-11-17
12-04-17 11:56 AM - Post#2716858    
    In response to Jalapeno

Hi guys, I see some of you use DOT 5, then I assume it is Silicone based and not DOT 5.1 polyethylene-glycol based. How is your experience with silicone based brake fluid in a Treadle Vac? What do you use to grease when assembly the leather boot /felt?
Regards Svein from Norway (-56 BelAir 2DR HT with Dual Quads)



 


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