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Brake Problem

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Raymond

Raymond

Jedi Hopeful
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Hi All

im having issues with my brakes on Nigel

this past weekend i replaced the pads and hoses (W/braided Steel) on the front of the car bleed the brakes (with the car off) had a great firm pedal
but when i turn the car on the peddle drops ,not to the floor but a few inches

then when in driving around town sometimes when i apply the brakes the peddle drops to the flood like it isnt even attached to anything but the brakes will pump back up i have bleed the brakes a few more times same result and now i have parked the car till i can fix this issue

i dont have a brake warning light po removed the sensor at the propvalve(junction box)


thanks for the advice

Ray
 
OH i forgot to mention that i cannot find a leak and im not loosing any brake fluid
 
I have no idea about the brake problem, but I think we should have a thread devoted to photos of Dads and Daughters in named MGBs /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
Are your rear brakes adjusted properly? If they're adjusted too loose, you'll have excessive pedal travel.

Pedal dropping to the floor and being able to pump it back up seems to indicate air in the system ~somewhere~. It would probably be a good idea to flush the entire system.

Sorry, the only suggestions I can think of are to keep bleeding the system, and ensure the rears are adjusted properly.

I'm not sure why you would have softer pedal response with the engine running. I think a '69 does not have "Power Brakes" in stock form. So, in theory, your brakes should be the same with the engine on and off.

Does the steering pull to one side or the other under hard braking? That might help narrow down where the air pocket is (side opposite of the pull).
 
Nunyas said:
...I'm not sure why you would have softer pedal response with the engine running. I think a '69 does not have "Power Brakes" in stock form. So, in theory, your brakes should be the same with the engine on and off...
Click to expand...

Actually, I just thought of something that may affect the pedal feel between Engine on and Engine off. The parking brake. If you bleed your brakes with the Parking brake set, you will ~always~ have a firmer feel with the brake on versus off.

I think I'd look at those rears first /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
doesnt pull at all

and i havent adjusted the rears yet

the peddle goes down farther than before the new pads and hoses
 
i didnt have the parking brake on

i had the car on level ground
i blocked the rear wheels and had my wife slowly pump the peddle


i think im going to start replacing the rear brakes
 
well heck, I'm all out other than keep bleeding and looking for that elusive air pocket.

Have you tried one of those 'EZ Bleed' type kits? They have a check valve in the end and seem to work a lot better than any amount of pump, hold, open, close, repeat system I've used before getting one myself.
 
Could you be allowing air to get back into the system when your wife lets up on the peddle? It is best to put a hose over the bleed screw running down into a small jar. The end of the hose gets submerged in brake fluid in the jar and can't siphon air back into the system when the brake peddle is released. If there is air coming out of the system, bubbles show up in the jar. Always start the bleeding process at the wheel farthest from the MC. Always bleed all 4 wheels.
 
Field test for a failing master cylinder(which hopefully you don't have, but I'd thought I'd pass along, so you can rule it out)

With the engine running press on the pedal a couple of times to build pressure, shut the engine off, keeping light pressure on the brake pedal DO NOT LET YOUR FOOT OFF THE BRAKE PEDAL. Keep the pressure on the pedal for 2-3 minutes continuously. You do not want panic stop stab pressure, just light to moderate(slowing for Granny in the crosswalk avoidance) pressure. If the pedal drops during the 3 minuts this is indicative of the master cylinder seals leaking internally.

I suspect though that you still have air in the system.

What I do is with an assistant in the car, master cylinder full, keep a clear vinyl tubing on the bleed valve going into a bottle with a small amount of fluid in the bottom, tube under the fluid level. Have your assistant pump the pedal three times slowly, then while she/is is holding(have them announce "holding" or some such code, you open the bleed valve. They keep their feet on the pedal, and let you know when it drops to the floor "all the way to the floor" you tighten the bleed valve. Repeat three to four times each bleed valve, starting at the furthest from the master cylinder.

This system has worked for me for better than 30 years, so I credit it as a successful bleeding procedure.
 
thanks for all the info and advice im going to try to bleed with the hose jar method but im also going to try the master cylinder field test

i was going to replace the master cylinder later in the restoration process just as a safety issue


i dont think it is the master because everthing was fine before I started working on the brakes


Thanks
Ray
 
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