Yet another brake bleeding question

[House Money]

I've searched but didn't really find an answer for this. I did bench bleed the masters, then gravity bled all four corners, then used my Mityvac on all four corners. I've had the Mityvac for many years and I question if it is working correctly as it does not hold vacuum for very long at all.

At this point I can, using my arm as I do not have any interior installed yet, push the brake pedal all the way until in contacts the frame tube. I had my wife hold the pedal there and I could not rotate the front rotors, didn't try the rears as there are so hard to turn anyway. But I do suspect my problem is in the rears.

On to my actual question: When I adjust the master cylinder push rods as described in the manual for setting up the balance bar, the bar is angled just like the manual shows, but when I depress the pedal the balance bar actually angles the opposite of what the manual shows for heavy pedal effort.

What is this telling me? That the rear is still not bled completely? The rear master cylinder is defective? No matter how I adjust the push rods my balance bar ends up angled more like the no pedal effort picture.

Thanks in advance, Gary

[House Money]

62 views and no responses - so I thought maybe I would add some pictures to see if that helps. First picture is with the push-rods adjusted pretty much like the manual shows: DSC_0614.JPG
Next is with the pedal depressed half way, the manual shows that at this point the balance bar should be about even, mine is not: DSC_0615.JPG
Last picture is with the pedal fully depressed and touching the frame, the manual shows the bar should be angled like this: /, as you can see mine is not: DSC_0616.JPG

Any ideas what this is indicating??

Thanks, Gary

[edwardb]

Actually, unless your manual is different than mine, you don't have the MC's installed how it's described in the manual. It says (1) cut 5/8-inch off the end of each pushrod, then (2) thread the shafts in until flush on the other side of the mount (clevis). Yours are set to different lengths. I don't know if that would help what you're experiencing. But a starting point would be how the manual shows. Has worked for me.

As far as bleeding, I've used pressure bleeding on every build and hasn't let me down. I've been using CNC reservoirs and they sold a cap with a Schrader valve and was easy to do. No touching the brake pedal. In fact that could mess up the process in a hurry. My Coupe build has Tilton reservoirs (no more CNC...) so made my own pressure cap and followed the same process. Also worked just fine. I'm not familiar with the Mityvac.

[RoadRacer]

Funny, my manual doesn't mention this shortening of the pushrods that everyone mentions recently. I just re-read that section.

Anyway, one thing you didnt mention checking was the different sized master cylinders.

And since you can mount them whichever way you prefer, is your pic with front at top (0.75 stamped on casting) and rear at bottom (62 stamped)? Or the other wayaround? I ask because I've mounted the front in the middle (clutch, front, rear)..

[RoadRacer]

One more thing.. I CANNOT push my brake pedal by hand - did you mean by hand?!! Mine barely moves half way using as much arm effort as I can. I need feet on mine.

[House Money]

I can push my pedal by hand until it hits the frame, I have .75 M/C's both front and rear. I did shorten the rods by 5/8" as directed and I do have mine plumbed as the manual shows - I'm looking at page 128 of my rev G manual, the push rods are threaded in different lengths in that section of setting up the balance bar.

[edwardb]

I can push my pedal by hand until it hits the frame, I have .75 M/C's both front and rear. I did shorten the rods by 5/8" as directed and I do have mine plumbed as the manual shows - I'm looking at page 128 of my rev G manual, the push rods are threaded in different lengths in that section of setting up the balance bar.

My apologies. I'm looking at a Roadster manual and you're clearly working on a '35 Hot Rod Truck here. I have no idea why they would be different, but apparently they are? Sorry for any confusion. I can only say I've started with them the same length on the Roadster and Coupe builds where I also used the Wilwood pedal box and all worked out fine. Same with the pressure bleeding I mentioned before. As far as pedal effort, the ones I've done you can push the pedal down by hand. Obviously can put more pressure on the pedal with your foot. But still goes to where the brakes are working when pushed by hand.

[Motor_Freak]

My front Wilwood MC start leaking after 500 miles. Will replace both with Tilton.
It's a lot of work!!!
I know it's offtopic, just saying..

[RoadRacer]

As far as pedal effort, the ones I've done you can push the pedal down by hand. Obviously can put more pressure on the pedal with your foot. But still goes to where the brakes are working when pushed by hand.

Sure, I didn't mean to imply you couldn't apply brakes by hand - just that my pedal is rock hard at half travel and brakes are all fully engaged. I can't push my pedal anywhere near the chassis - so it seemed there must be lots of air if you can push to hit the frame? And if there's air in one/both ends, it would explain the bias bar.

[sethmark]

The problem is you have a ton of air in your lines. The mityvac is worthless. I know some people can make them work, but for the most part they just create more problems. You want to pressure bleed from the top down not from the bottom up. I strongly suggest that you look into the motive power bleeder. Not only can you pressurize the system and let it sit and see if it bleeds down, it will also bleed the brakes without two people. Once you have the brakes bled, you can worry about the balance bar. No matter what, you need to adjust your brakes more than once when you have a drivable chassis.

worrying about the balance bar before you have the brakes bled and are able to drive a chassis is putting the cart before the horse.

[DavidW]

The Mityvac and the Motive power bleeder both work just great, I have both and use both, the Mityvac is more convenient to use. Anyway you may have a bad master cylinder, and it doesn't need to leak fluid to be bad. The seals internally can go bad and cause what you're experiencing, It happened to me. Everyone told me I had air in the lines and I didn't bleed the brakes correctly.

If you used the Mityvac and bleed the calipers at the top bleeder screws in the following sequence you should be fine, PS rear, DS rear, PS front, DS front. If that didn't give you a solid pedal after a couple times you have other problems and it could be one or both of the master cylinders. Replace both of them and see if that helps.

[House Money]

Thanks for all the replies, clear I still have work to do. Sethmark: Do you by chance know which of the Motive bleeders would be the one to get? They don't seem to offer one for a '35 FFR truck - WTH??

DavivW, are you saying that you in fact had a bad M/C? And, I did bleed in the order you mention, both gravity and with the Mityvac - although like I mentioned already I think mine is tired and worn out and may not be working like it should.

Gary

[sethmark]

Gary, depends on the master reservoir. . I used round reservoirs and took their round screw on style, which has a rubber gasket inside and clamped it to the master. I pressurized the system repeatedly before adding fluid and found a bad caliper.

[House Money]

My reservoirs are round too but look different that yours. So the cap doesn't screw on?

[sethmark]

Nope. Look closely in the background. 2 clamps. It pressurized like that a 15psi for an hour without bleeding down.

[JimLev]

I have a newer version of the Motive that has a screw on cap, a seperate fill cap, a pressure gauge, and quick disconnect fitting.
I used it as well as a hand vacuum bleeded at the caliper. Think I got it at Eastwood, HF also sells one that seems to be better (metal not plastic) than Eastwood.
Before I started I filled up the small reservoirs on the ends of the master cylinders.

[House Money]

I saw the clamps - that's why I asked. My reservoirs are powder coated so I would have to be careful using clamps to hold the cap in place.

[DavidW]

Yes, I had a bad master cylinder, I replaced it and bleed the brakes and they work great now.

To use the Motive bleeder get a replacement cap for your master cylinder drill it, thread it, install a fitting and hose and use it with your Motive Bleeder. Be careful not to let your reservoir run empty.

[House Money]

Yes, I had a bad master cylinder, I replaced it and bleed the brakes and they work great now.

To use the Motive bleeder get a replacement cap for your master cylinder drill it, thread it, install a fitting and hose and use it with your Motive Bleeder. Be careful not to let your reservoir run empty.

What was the indication that you had a bad master cylinder? I like your idea of getting an extra cap that I could drill & tap, with FFR being closed do you know where I could obtain one? And at that point would I even need the Motive bleeder or just use my compressor turned way down, or even a bike pump?

[DavidW]

What was the indication that you had a bad master cylinder? I like your idea of getting an extra cap that I could drill & tap, with FFR being closed do you know where I could obtain one? And at that point would I even need the Motive bleeder or just use my compressor turned way down, or even a bike pump?

Long story short, indication was my brake pedal would go soft after I had a hard pedal after bleeding them.

Contact the manufacturer of the reservoir you have and see if they offer caps for sale.

Yup, use low pressure, 8-10 psi.

[House Money]

I went ahead and bought a Motive bleeder, got their model # 0250 that comes with multiple adapters, one of them (#1100) actually fits the reservoirs that came with my truck kit. So I have a question: can I use this without brake fluid in the bleeder? The reservoirs are full so can I just use air pressure generated by the bleeder to push the fluid through the lines? Just have to make sure the reservoir doesn't go dry.

Gary

[sethmark]

It works by forcing non aerated fluid through the lines, so pushing air into the lines will only introduce more air, not bleed air. Fill the motive tank, pressurize the system and wait. See if it holds pressure. If it does, crack the rear passenger and start making your life better.

[RuffShod]

Stupid question....

Have you made sure that the bleeders on your calipers are orientated correctly?

[House Money]

I thought I would post a wrap-up to this. As mentioned, I purchased a Motive pressure bleeder, but against advice given here I decided to try it dry. I went to my local Hazard Fright store and bought a 1/4" male quick disconnect fitting and a couple of female plugs. DSC_0631.JPG

Then I simply pumped the unit up to 15PSI, screwed the #1100 adapter to the reservoir, connected the two and watched for a few minutes to see if the pressure held. Once that was confirmed I started bleeding the rear brakes in the normal sequence. I did this three times, disconnecting and removing the adapter so I could refill the reservoir and then check the pedal, each time it got a little firmer. Then I went to the front brakes and was shocked at how much air I got from the right side caliper! The left just flowed fluid so I disconnected the bleeder and now I have what I consider a solid pedal. I say "what I consider to be a firm pedal", but what exactly is a firm pedal? Mine gets very firm and stops probably about two inches from contacting the chassis, does that seem right?

I have to say that using the Motive bleeder dry has to be the easiest way to bleed brakes - and zero clean-up! Also, I saw zero evidence of this method causing any sort of aeration of the brake fluid.

Gary

[sethmark]

The location of the pedal is determined by the balance bar adjustment and the depth of the threaded piston on the master. The motive bleeder works so well its criminal. If you fill the reservoir in the bleeder you don’t have to mess with fluid at all. It refillls as it goes.

[House Money]

Yes, but then you have to clean the bleeder when you are done, not so with how I did it.

[sethmark]

I have to be honest, using the pressure without the fluid makes me worry about bubbles. Maybe I’m paranoid, but the amount of fluid I can push through a line using the bleeder as nature intended is substantial.