scrappie

Once again I turn to the wealth of knowledge here on this website. I have a 1971 442 conv. that I just took out of storage. I have not driven it in 8-9 years. I am planning a resto but cant seem to raise the money or find the time.
I have decided to just drive it and fix along the way little by little.
I started with the brakes: The pedal felt a little soft a while back so I changed out the master cylinder. The pedal isnt soft anymore, now it seems like it only catches at the bottom when I press the pedal. It seems like there is no boost at all? I then thought maybe a stuck caliper or something so I changed both calipers and wheel cylinders and another master cylinder and drained all old brake fluid. I bled the system and got new fluid to all four wheels. The left front was the hardest to get fluid to come out of for some reason but it finally did. The pedal still feels the same! like when the car is off and not running? I took it for a spin and it is scary. I really have to press hard to get it to stop. it also pulls to the right when I hit the brakes.
The only things I have not changed are the brake booster and the metering valve. Is there anything else? How do you test the booster and metering valve? Have I missed something? I also converted to silicone brake fluid. Thanks in advance to all.

brown7373

You said you have changed everything, but made no mention of the rubber hoses. Have they been replaced?

Tony72Cutlass'S'

Sounds like you're getting terrible vacuum to your brake booster.

Do you have a vacuum gauge and is your booster properly connected to FULL manifold vacuum? Not ported?

Guttermouth

You can simply check the booster by holding down the brakes and then start your car and see if the pedal drops down because you now have vacuum.

Also what brown said, check your rubber hoses, if they are old and dry/worn they could bubble up and eventually fail.

when your draining the brakelines make sure you start with the wheel furthest away from the master cilinder and work your way to the closest one.

so check: vacuum hose from engine to booster, vacuum itselve by starting and holding down the pedal, and check rubber hoses.

greetz,
Clint

m371961

Having a hard time getting fluid out of the left side and having car pull to the right are related. Problem with rubber hose on left side?
Pedal problem sounds booster related.

AZ455

Does the peddle depress easily up until the point your start to feel the brakes grab? How's the push rod length? This shouldn't be an issue though, unless your new MC is different.

droldsmorland

Do yourself a favor and purchase the bug sprayer pump style brake bleeder from Jegs. It’s the best $60 you’ll spend for quite a while. Change all 3 rubber lines with high quality OEM replacements not Chinese crap and bleed the system starting from the furthest from the master (passenger rear) working your way towards the drivers front. Make sure the rear drum shoes are adjusted up so you get ever so slight friction on the drum on both sides. Depress the caliper pistons in with a Big AZZ set of Channel Locks or C clamp. Do they go in nice and smooth? If not replace. Make sure the caliper slider O rings are lubed with the silicone brake grease. Do the booster check mentioned above. This should take care of it.
If the car pulls to the right the left caliper isn’t engaging the rotor or the right sides hanging up? I suspect air in the lines or a bad caliper. Just because its new doesn’t guarantee its good.
Let us know what the fix was?

scrappie

Thanks for the responses. I'm gonna check all that stuff this weekend hopefully. I have not changed rubber hoses but will. The pedal depresses easily up until the last inch or so.

scrappie

I wanted to update you guys on my problem:
I got home from work today and replaced both front rubber brake hoses in my 71 442. I bled them best I could with my 7 yr old son. I took it for a spin around the neighborhood and the front brakes seem to grab better and evenly (no more pulling to the right) After I got the old lines off I tried to blow through them to see if they were blocked. The left one barely let air through and the right one was a little better. I tested the new ones before installing them and I was able to blow through them with little resistance. I have the rear rubber brake line also but have yet to replace.
The pedal still feels like it's not being boosted so I pressed the brake with the car off and then started the car, waiting to see if the pedal went down and it did a little one time but then after testing it the same way it didn't move when I started the car again. I am gonna check vacuum at the booster, I am also gonna re-bleed the rear brakes and adjust them to see if it makes a diff. I have a brand new brake booster in the box ready if I need it? Any other tests for the booster? I am getting there, progress is good. Thanks for all the help.

m371961

Thanks for letting us know what you found.If it was me, I would just go ahead and replace booster and rear flex line. And replace the vac line to the booster. If you have the parts, you will feel better driving it knowing the parts are new rather then driving it somewhere and having a problem.

musicars

You can also check to see if the booster is holding vacum by running the engine, then shutting it off. Wait a minute, then pull the check valve out of the grommet on the booster. There should we a rush of air as it is sucked into the booster. If the booster does not hold vacuum then it is leaking or the check valve is leaking. When my old one went out it didn't hold vacuum at all. The new one will hold it for several minutes or until I step on the brake.

scrappie

So my brakes work and I have been driving the car. I am not getting boost so its still a problem. I can here a hiss when the car is running and I have my head under the hood. I checked everything on the top of manifold and then found the source to be coming from the bottom side of the MC flange where it mounts to the booster. Is there supposed to be vacuum there? or is this an indication that the booster has failed internally?

droldsmorland

There is a rubber boot/seal between the Master and booster. Thats most likey whats bad. Inspect it. You can get the MC out of the way w/o removing the lines. Id try that first. Let us all know where you sourced the seal please.

ah64pilot

Your engine ought to run better once you fix the vacuum leak at the booster That's an easy swap, git r done!