No brakes

[pagoda113]

Real strange one. Have just replaced my front calipers and pads for new ones. The problem I now have is as follows.
When the car is not on running I have normal pressure feeling on the brake pedal. Now when I turn the car on running the brake pedal is floppy with no pressure feeling when pushing down in it. Yes I have bleed the system at same time and checked for any obvious brake fluid leaks.
I have ordered new check valve coming Wednesday. This car is my 1967 USA spec left hand drive.
Look forward to suggestions to my problem.
Thankyou

[ja17]

Make sure the calipers are mounted with the brake bleeder at the top! You can accidentally mount them on the wrong side of the car, which makes the bleeder at the bottom. Otherwise the brake master cylinder may have failed.

[pagoda113]

Thanks for reply and you got me checking my pictures. I have just noticed my bleed screws is at the bottom. Does this really make a difference ?

[ja17]

Most definitely! With bleeders at the bottom, the calipers remain full of AIR!

[pagoda113]

Ok someone well embarrassed here and makes sense in that you say. Now I know what I am doing this weekend lol.
Huge thankyou

[Benz Dr.]

I was going to suggest that as a possibility but thought better of it. I've been there too..........

[ja17]

Not that uncommon, someone else on this forum did it a few weeks ago! Most likely that is how I learned by doing it wrong many years ago.

[stickandrudderman]

I've seen professional garages make this mistake!

[Benz Dr.]

I've seen professional garages make this mistake!

Yup. Everyone makes mistakes; how you fix them is more important than the mistake. That's why we have liability insurance and do everything possible to not ever use it. Every shop has things that happen and if the problem is small, it usually gets fixed and no one hears about it. The last thing any shop owner wants to do is make that call about something big like a fire or accident.

[pagoda113]

Well I have done few over the years on my cars and cannot believe I made this mistake. Anyway all corrected and brakes now working as should be.
Thanks all

[gtait]

I have been restoring my 64 for the last number of years and have dismantled every nut and bolt with the exception of the rearend drive train. After reading this post I decided to check whether my bleed nipples were on the top or bottom, and sure enough they are on the bottom. The last time my car was on the road was 1985, so they have been that way for a while. I was planning on restoring the rear brakes later this month, but am not sure I would have caught this without this post.

Thanks

Gil

[Tom in seattle]

I usually use a “Mighty Vac” suction pump to pull brake fluid from the Master cylinder down stream to the wheel cylinder.  Wouldn’t that purge any air out of the wheel cylinder with the bleed valve at top or bottom? 

[stickandrudderman]

Does it matter? installing the calipers in the correct way is a very easy job that your life depends on.

[rgafitanu@gmail.com]

Mighty Vac will not bleed the air out if the bleed screw is at the bottom. In a hydraulic system air is being pushed towards the extremities and, naturally, up. The air trapped above the brake line inside the caliper will stay there even if you suck fluid from the bottom.

[waltklatt]

Wont work that way as the supply line is in the center of the caliper on inboard side and anything above is air.
So that's why the bleed screw is on farthest top portion to allow this 'pocket of air' to escape.