Chrysler Newport Brake Issue!!

[Cianmini1]

Hi everybody I’m from Dublin Ireland I’ve a 1965 Chrysler Newport 383.
I’m having an issue with my brakes.
It’s got power brake stock drums all round.
I went about doing some maintenance on the brakes due to have brake fade a few months back.
I ended replacing 2 front wheel cylinders due to the bleeder screws being rounded and I also replaced the master cylinder and brake line from the master to the proportioning valve.
The master cylinder I got was a (Centric) from rock auto it had a red sticker in the box stating “Do not Bench bleed”.
I have so far adjusted all 4 wheel drums till there is contact and I can feel the shoes dragging.
I have bled the brakes multiple times from the Right hand rear to the front left which results in a good pedal with the car off! And once the car starts and it’s in neutral or park it’s still fine but once it’s in drive the pedal goes soft and just before the floor il have a resistance!
There is no rod adjustment on the master with a nut like some master cylinders.
If I do pump it 3 times while
I’m driving I will get a hard pedal back!
So I’m left with 2 options that I can think of that I still some how have air in the system or the new master cylinder is bad? Or I am in fact supposed to bench bleed the master even though it says not too!
I hope someone can help me!! Very stuck!
Hopefully I’m overlooking something stupid!
Thanks very much guys!!

 

[FURYGT]

After you drove the car with the pedal going soft, did you check the master cylinder fluid level?

Are sure that there isn't a leak somewhere?

Was the master cylinder a new unit or a rebuilt/remanufactured unit?

 

[Big_John]

I think you still have air in the system somewhere.

Are you using a conventional brake fluid? Not silicone that is.

it had a red sticker in the box stating “Do not Bench bleed”.

Quite frankly, I've never seen or heard of a master cylinder that had "do not bench bleed" on it. Since the sticker was "in the box" rather than on the MC, I'd say it was some sort of mistake.

So, if it were me, I'd bench bleed that MC first.

 

[Sixpactogo]

I believe you have some air in the system yet. I have never seen a note saying "do not bench bleed". I can't imagine anyone believing there is a better way even though you can sometimes get by not doing it but IMO it is the best and easiest way. Either way, since you didn't, I would bleed the whole system again and maybe even a third time before starting to replace parts again. Not to say your master is not good but they have been known to be bad from the start.
By the way........You don't have a proportioning valve with 4 wheel drums. You have a metering block and if you can bleed all 4 wheels, your metering block is not the problem.

 

[413]

Make sure they are adjust properly. The shoes too far from the drums will do this also.

 

[Cianmini1]

After you drove the car with the pedal going soft, did you check the master cylinder fluid level?

Are sure that there isn't a leak somewhere?

Was the master cylinder a new unit or a rebuilt/remanufactured unit?

Hi yes the fluid is at the same level!
No leak at all!
It was a new part!

 

[Cianmini1]

Make sure they are adjust properly. The shoes too far from the drums will do this also.

They adjusted nice and tight all round! If I brake now I can hear they contacting so I guessed that will go away after they settle in

 

[Cianmini1]

I believe you have some air in the system yet. I have never seen a note saying "do not bench bleed". I can't imagine anyone believing there is a better way even though you can sometimes get by not doing it but IMO it is the best and easiest way. Either way, since you didn't, I would bleed the whole system again and maybe even a third time before starting to replace parts again. Not to say your master is not good but they have been known to be bad from the start.
By the way........You don't have a proportioning valve with 4 wheel drums. You have a metering block and if you can bleed all 4 wheels, your metering block is not the problem.

Hi thanks ! Sorry yes it must be the metering block!
Il try bleeding one more time! If not il
Bench bleed the master cylinder!
Thanks

 

[Cianmini1]

I think you still have air in the system somewhere.

Are you using a conventional brake fluid? Not silicone that is.




Quite frankly, I've never seen or heard of a master cylinder that had "do not bench bleed" on it. Since the sticker was "in the box" rather than on the MC, I'd say it was some sort of mistake.

So, if it were me, I'd bench bleed that MC first.

I was using millers 300 high performance brake fluid in it! Just for a higher boiling point!

 

[Big_John]

I was using millers 300 high performance brake fluid in it! Just for a higher boiling point!

OK. Sometimes folks have issues with bleeding silicone fluid, so that eliminates that possibility.

When you pump up the pedal with the car running and you say that then you have a hard pedal, does that pedal stay hard when you push, or does it slowly sink to the floor?

The goal is to have a pedal that's rock hard with the engine off and no vacuum in the booster. That is checked simply by pushing the brake pedal a couple times with the engine off to bleed off the vacuum, then let it sit for a minute and press your foot on the pedal It shouldn't move very much, if at all, and it should stay rock hard as long as you have your foot on the pedal.
<insert some sort of Viagra joke here>

 

[Cianmini1]

OK. Sometimes folks have issues with bleeding silicone fluid, so that eliminates that possibility.

When you pump up the pedal with the car running and you say that then you have a hard pedal, does that pedal stay hard when you push, or does it slowly sink to the floor?

The goal is to have a pedal that's rock hard with the engine off and no vacuum in the booster. That is checked simply by pushing the brake pedal a couple times with the engine off to bleed off the vacuum, then let it sit for a minute and press your foot on the pedal It shouldn't move very much, if at all, and it should stay rock hard as long as you have your foot on the pedal.
<insert some sort of Viagra joke here>

Hi yes! Engine off the pedal is Rock hard! If I pump it will stay hard and press it won’t depress much at all.
Think I’m gonna bench bleed to be honest!

 

[Just Carbs]

Put some towels under it and bench bleed it on the car.

 

[Cianmini1]

Put some towels under it and bench bleed it on the car.

 

[Cianmini1]

Just disconnect the lines and connect the bench bleeding kit? And pump the pedal?

 

[Just Carbs]

Just disconnect the lines and connect the bench bleeding kit? And pump the pedal?

Or disconnect the lines one at a time and hold your finger over the port while your helper pumps the pedal for you.

 

[Cianmini1]

I’ve only got 1 outlet on my master! It’s just a single pot! So il screw in the bench bleed kit and pump the pedal!
Thanks for your advice!

 

[Just Carbs]

I’ve only got 1 outlet on my master! It’s just a single pot! So il screw in the bench bleed kit and pump the pedal!
Thanks for your advice!

Living the dangerous life there.
I think the 67 Chrysler dual master is a direct fit.

 

[Cianmini1]

Really ok il look into it! For now il just try get this single pot working thanks

 

[Gerald Morris]

Really ok il look into it! For now il just try get this single pot working thanks

Read my thread: A Poor Man's Master Cylinder Upgrade. I had a '66 Newport. Ditch that single pot Centric thing.

 

[Just Carbs]

Really ok il look into it! For now il just try get this single pot working thanks

A man ain't a man till he survives a complete no brakes situation at 60 mph going downhill.
It was a very exciting 10 seconds.