# Pedal to the Floor: Opinions Please



## Koppster (Jul 27, 2008)

Leaving work last night, I started the car, backed it out of the parking spot and drove about 150 feet to our security gate. Applied the brake and the pedal went all the way to the floor. I released, pumped once, twice at most and the pedal came back solid. Drove 30 miles home, no issues. Checked brake fluid and looked for leaks. No problem

Car has front disks, rear drums, system looks to be fairly new. I replaced the master cylinder in February because of seepage. This is the first time I've had any brake issues.

I'm thinking it was a low vacuum situation. Car has an Edelbrock RPM Performer cam, 800CFM carb and I had the new AC system on when I started the car and the car had been sitting for about 4 hours....result being very low idle with a pretty heavy lope (sic). 

Personal opinion, low vacuum problem....nothing to worry about, cost of doing business with a cam and AC. :confused

Thoughts?

Thanks
Rick


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## geeteeohguy (Feb 2, 2008)

Low vacuum will cause the brake pedal to get harder if you have a vacuum power boosted brake. The only thing that will let the pedal drop to the floor is hydraulic fluid being displaced: either the master cylinder is bypassing, or your brake pads were compressed back into the calipers (like when you repack the bearings). If no external leakage, I would bet on the master cylinder bypassing. It's an internal leak past the primary cup seal in the master, and you won't have external leakage.


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## auburnconsulting (Nov 3, 2008)

geetoguy is correct. no vacum hard pedal. no pedal is no pressure in master. we are fighting the same problem in my sons tahoe. it has abs and a low pressure sensor. we get no codes or lights. we have slowly replaced everything but the abs unit. including lines. we started at the calipers and wheel cylinders and went all the way to the master. still no better.


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## Koppster (Jul 27, 2008)

Thanks guys....weird, it has only done this once and there doesn't appear to be any fluid loss in the master cylinder.

Just checked the warranty on the master cylinder from Inline...30 days! Wow, I'm very impressed. I think it's time to find a new brake part source.

Going to drive the car today to see if I can get an encore....


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## Too Many Projects (Nov 15, 2008)

Koppster said:


> Thanks guys....weird, it has only done this once and there doesn't appear to be any fluid loss in the master cylinder.
> 
> Just checked the warranty on the master cylinder from Inline...30 days! Wow, I'm very impressed. I think it's time to find a new brake part source.
> 
> Going to drive the car today to see if I can get an encore....


I thought it was a year. At 30 days mine is expired and I've never driven the car.....


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## geeteeohguy (Feb 2, 2008)

Koppster, you won't lose ANY fluid when a master cylinder bypasses. Also, they seem to do it intermittantly, and sometimes more on a hill. Go figure. Good luck with it!


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## Koppster (Jul 27, 2008)

Okay...here are today's observations:

1. When I backed out of the same parking spot with the wheel cranked hard to the right I got a repeat, pedal to the floor and then it pumped right back up.

2. I'm hearing a clunk/thunk from the right front wheel area, cannot feel it through the pedal but I can feel it lightly through the car. Thunk is louder sometimes than others. Always follows brake pedal depression by a fraction of a second or more.

Bad caliper? Bad hose?


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## geeteeohguy (Feb 2, 2008)

Loose caliper mount/loose wheel bearing. Not a hose. I would check it out before I drove it!!!!


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## Koppster (Jul 27, 2008)

Jeff...that works for the noise but how does the pedal loss factor in? To your point, there has to be some bypass action going on somewhere.

I just went out and did a grab/shake on both front wheels, feel solid. I'll put it up on the jackstands this weekend to check it all out.

Thinking seriously about just ordering two calipers so I can baseline this car and drive with confidence.

BTW...I'm an Inline fan again... Kevin (Inline rep) just called me and they are going to warranty the master cylinder even though it is 90 days past warranty. I AM IMPRESSED.


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## geeteeohguy (Feb 2, 2008)

Koppster: the pedal loss comes in if a caliper orcaliper pad braket is loose. The caliper piston will keep extending out of the caliper bore, and your pedal will keep dropping. If you've ever repacked a set of wheel bearings on a disc brake car, or relined a disc brake set-up and have tried to drive the car withour first pumping up the pedal, you'll know what I mean! The brake pad has to contact the rotor to stop the caliper piston from extending. If the caliper is loose, the piston keeps on travelling, and you have no or low pedal.


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## Too Many Projects (Nov 15, 2008)

Koppster said:


> Jeff...that works for the noise but how does the pedal loss factor in? To your point, there has to be some bypass action going on somewhere.
> 
> I just went out and did a grab/shake on both front wheels, feel solid. I'll put it up on the jackstands this weekend to check it all out.
> 
> ...


If turning the wheels hard right is causing it, you should be able to duplicate it anywhere. I agree with Jeff, something is loose and allowing the piston to contract in the caliper. The clunk is a big concern; ie loose ball joint letting the spindle flop around. I can't picture in my head how that would let the caliper move though. I suggest trying to duplicate the condition at home and then look at the position of everything with the wheels turned to see if there is interference somewhere. I'm concerned for your safety Rick, this could be a warning sign of a sudden, catastrophic failure. Proceed with caution....


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## Koppster (Jul 27, 2008)

Drove home last night without incident (27 miles). No shake, no shimmy, no pull, no tug. Tracks straight, steers completely normal. Interesting, no clunk at speed.

However, I'm convinced something is wrong with the caliper and it is linked to the pedal/hard right thing. Car is in the garage today, I'll put it up on jacks tomorrow AM and check it all out. I like Jeff's thoughts about loose caliper, I can see that given all the symptoms.

More to come.....

Rick


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## Koppster (Jul 27, 2008)

Okay, pulled the front wheels off and I can't find anything loose, missing or obviously broken.

The right upper ball joint has some rubber peeling back on the boot, it will need eventual replacment but that's all I saw.

I'm back to thinking caliper problems that aren't apparent to the eye and maybe a flaky master cylinder to spice things up (bypass).

Thoughts?


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## Too Many Projects (Nov 15, 2008)

Have you turned the steering hard right to see if you can feel anything in the wheel ? Go look where everything is in relation with it turned. Do you have someone that can turn the steering while you watch ? Might see something binding or jump. Anything look out of place ? Place the jack under the lower arm and jack it up a couple inches and then pry up on the upper control arm at the spindle to check for upper ball joint play. Do the same on the lower for play.


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## 68greengoat (Sep 15, 2005)

That's what I'm thinking too, TMP. I wonder if the ball joints are shot. When were the ball joints replaced last? May be time to replace them all..... I had a guy test mine out. Initially he said they were good. Turned out they all were shot.


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## Koppster (Jul 27, 2008)

Hmmm.... could this be an excuse for tubular upper & lowers?


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## Too Many Projects (Nov 15, 2008)

Koppster said:


> Hmmm.... could this be an excuse for tubular upper & lowers?


Find and fix the cause of the pedal fade first and then it would be a natural sequence to continue with the altered geometry uppers for better handling.....:cool. Very little benefit from the lowers unless you are thinking coilovers too...


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## geeteeohguy (Feb 2, 2008)

Bad ball joints wouldn't affect brake pedal height, since the calipers mount to the spindles. Something is causing a caliper to shift when it's turned full lock, compressing the piston back into the caliper, and causing low pedal when brakes are applied. You need to try to simulate the conditions that couse the problem. Sounlds like you need someone in the drivers seat, and another under the car with a good light. Good luck.


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## geeteeohguy (Feb 2, 2008)

Just a thought: is the caliper hitting the A arm on full lock, causing it to compress> That would couse your problem.....


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## Koppster (Jul 27, 2008)

Okay...I might have found something.

If you look close in these pictures you will see the sway bar (I belive it is the sway bar) is hitting the right front hose connection the caliper. Also, the bolt for the sway bar contacts the hose as well. :confused

It's more than just contact, there is some pressure being applied at full right.

PS, I took these pictures with the wife in the seat turning the wheel...motor running for the power steering of course.


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## Too Many Projects (Nov 15, 2008)

That could be pushing the caliper outward which would compress the piston. Does the contact happen before full turn and look like it's pushing the caliper ?
I noticed in the first set of pics that the sway bar link is leaning out and back. The bar is too wide for the car. The links should be very near vertical.


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## geeteeohguy (Feb 2, 2008)

Koppster, you have posted photos of your problem. It will go away when you fix the sway bar clearance problem. As TMP stated, the bar is pushing the caliper body, compressing the piston. It's a "floating" caliper, and every time you turn it to lock, you're pushing the piston way back into the caliper bore. Then, when you hit the brake pedal, you have about 1/2 inch of space between your inner brake pad and the rotor! YIKES! get rid of that sway bar!!!!!


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## Koppster (Jul 27, 2008)

Okay, I guess Ames/PY are going to get all my money eventually anyway. 

Wonder why that bar is wide...


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## Too Many Projects (Nov 15, 2008)

Koppster said:


> Okay, I guess Ames/PY are going to get all my money eventually anyway.
> 
> Wonder why that bar is wide...


It could be off a different model. I measured mine today for reference. It's 41" center to center of the bolt holes and about 14 inches from the center of the frame mount to the center of the bolt hole. Hope that helps determine if it's not the right one. My other thought is that it could be original and as disc brakes weren't an option in 64, it didn't have to clear a caliper. Maybe one like mine, which should be correct for a caliper, would fit better. I have an extra one that I got on my replacement frame. If you want it, just say so.........
As long as you know what's causing the condition now, you can make a mental point to not turn the wheels to full lock and avoid the no pedal. I WOULD cut off the excess threads on the bolt before they cut the hose though.


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## Koppster (Jul 27, 2008)

Okay, I agree, the contact with the calipers is a likely culprit. Here's my approach:

I've ordered new calipers and steel braided hoses. I've been wanting to baseline the brake system in this car anyway.

I'm not ready to give up on the sway bar yet, it may be a bad marriage between current calipers and the bar. See this post I put on PY (they have more 64 owners, wanted pictures): 64 Front Stabilizer Bar Pictures Please - PY Online Forums

Should have parts by Friday, will do the work on Saturday. 

Thanks All...more to come. :cheers

PS: I need to look at my sway bar with the wheel straight forward. I've looked at pictures of the mounting bolts in catalogues and it appears the bar may tilt them when you turn. Wonder if mine are vertical with wheels straight forward. :confused

Rick


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## geeteeohguy (Feb 2, 2008)

Rick, new calipers and lines will look pretty, but won't fix your problem. You need to install a different sway bar, or perhaps install shorter link pins (The pins that hold the bar to the A-arm). Even braided steel covered brake lines won't do too well rubbing against a sway bar bolt....


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## Koppster (Jul 27, 2008)

geeteeohguy said:


> Rick, new calipers and lines will look pretty, but won't fix your problem. You need to install a different sway bar, or perhaps install shorter link pins (The pins that hold the bar to the A-arm). Even braided steel covered brake lines won't do too well rubbing against a sway bar bolt....



Jeff...no argument, you are right. However, I have been planning to replace the calipers anyway. A couple of my thoughts:

- There's a chance the calipers might be wrong for the sway bar
- I don't trust the calipers anymore given this experience
- Steel braided lines come from my motocross experience. Rubber lines would swell after over-heating and cause poor braking. I learned to respect steel braided line, if I'm going to replace them, might as well get those. 

Going to check with Mitch on the diameter of his bar, I want as thick as possible and of course new bolts, bushings, etc.


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## Koppster (Jul 27, 2008)

Well...solved one problem, one more to go.

The calipers were wrong for my car. The new 69-72 calipers fixed the sway bar contact. The brake hose attach point is down and to the rear. The calipers I had on there had the brake hose attach forward.

However, I did not fix the clunk/thunk sound coming from the right front when I hit the brakes. Need to investigate that deeper.

Here are some interesting pictures showing the difference between the calipers, the damage done and the new calipers installed.

Thanks all... more to come :cheers

Rick


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## Too Many Projects (Nov 15, 2008)

Wow, glad to see you got that mystery solved. When you put the new calipers on the brackets, did the right side fit snug fore and aft the same as the left ? If the bracket was worn it will let the caliper move back and forth and may be the clunk you hear when applying the brakes.. The ball joints could also be suspect, but they appear to have been replaced recently, not that they can't still be the problem.
You're turning into a regular 'chanic here, Rick....:cheers


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## d.reese (Apr 27, 2009)

Very informative thread, thanks guys.


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## Koppster (Jul 27, 2008)

Well I believe I have found the smoking gun...looks like a bolt worked loose on the right upper control arm bushing.

I temp fixed it this morning, no one has the cap/washer for it. Will order from Ames or PY.

Test drive okey dokey fine!! YAY! arty:

Thanks Everyone!

Rickster


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## geeteeohguy (Feb 2, 2008)

GREAT! Rick, two things: be sure to tighten the bolt with the vehicle sitting normally on all 4 wheels...not up on jackstands. You don't want to tighten it with the A arm hanging. It will twist the bushing and put a load on it. Also, WHERE ARE YOUR A-ARM SHIMS??? You should NEVER bolt an upper A arm directly to the frame....where are the alignment shims?? I would fix the bushing, and then drive it to an alignment shop for a front end alignment asap.


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