1971 Cuda (?) Help and Advise needed please

[Markh]

I recently bought a 71 E body from who is supposed to be the UK's best Mopar man. The car was sold to me as a "Daily Driver" car and has had a complete nut and bolt restoration. When I bought the car I was told that the brakes needed "bedding in". That is quite funny as the brake pedal is absolutely rock hard most of the time. The car is completely un-drivable as it it is. It has supposedly passed an MOT which tests the efficiency of everything on the car!
I have checked the vacuum to the booster and in "drive" I have 7 inches which raises to 10 inches in "park". The brake pedal "hisses" and slowly goes down and stops as if the booster is working okay.
Car has disc on the front and drums in the rear.
Engine is a 340 now with an 8 3/4 rear. Auto
The VIN nummber on the car (not sure what you call it over there) is BH23C1B134986
I know that it started life as a slant 6 and the numbers don't match but I bought this thing to drive everyday and not take it to shows on a trailer.
This is my first Plymouth (2nd E body) but I have 2 A bodies and several other USA made cars in my collection.
Can I have some help fro you guys on what I need to change so I can drive this thing every day and not just look at it
Thanks

 

[340challconvert]

Welcome to FEBO from New Jersey
Go to the intro section and introduce your self.

First thing I would do is to check the brake booster itself and the master brake cylinder that was used.
A slant six car most likely would have originally had drum brakes with out any power assist.
Make sure the brake master is for a disc brake car; they are different, master on a disc brake car would have a larger front reservoir. Also the proportional valve and other check valves in the engine compartment and under the chassis would be different and probably not changed.
The check valves help to regulate front to back brake fluid pressure.
Did this restorer buy a conversion kit to covert to disc brakes?
The brake master cylinders also come in different sizes. The factory bore diameter for a 340 car would have been a 1" bore which is no longer available. Replacements are often a little larger at 1 1/8.
I would go through the system from master to the valves to see what you have.

Check out this article; it could help.
http://www.moparts.org/Tech/MoparAction/Master_Cylinder.pdf

 

[KATSAAR]

pah is right,sounds like a miss match of parts.

 

[Grady Cain]

Welcome from NW CT USA.

 

[moparleo]

Welcome to the site. Sorry about the brakes but we will work it out.

 

[DetMatt1]

Welcome to the site from the Motor City!

 

[70Barracuda]

start watching Ramman vids on youtube. Dude knows and explains mpopar brakes well.

Do you have a bolt on master cover? Like to see a pic of master and booster w brake valve under.

 

[Markh]

Thank you for all of your replies, I really appreciate it
I will print off the link sent by paharamia and check out the Ramman on YouTube. I have taken some pictures and will try and see if there are any numbers on the master
Once again, Thanks for all the replies

 

[moparlee]

Welcome from mid Michigan. Keep us posted on sorting out the brake issue. Good people here to help you out.

 

[Markh]

 

[70Barracuda]

Looks like the correct booster
and master. The brake valve may be wrong. It should two separate blocks. Maybe I am nissing it in the pics?

Yes, I looked at mine. That silver bracket in your pic holds another block. Look at my thread customer service.

 

[340challconvert]

It does look like the factory 1971 booster w a replacement master cylinder.
There should be a proportioning valve and a distribution block under the master cylinder. Also, is that a flared copper brake line in your picture? Copper expands at a different rate then steel when stepping on the brake. If it is, not good; metal is much softer then the steel brake lines normally used and should be changed.
I attached pics of the original brake valving on my 70 A66 disc brake Challenger and the brake junction valve under the driver's side rail. I have the two piece brake line from front to back axle. (Some e bodies had a one piece)
One other thing, check the brake rod from the booster to the back of the master; make sure it is not jamming up.

 

[Markh]

Good Evening
I have been busy watching Ramman videos (thanks 70Barracuda) and after paharamia pointing me in the right direction I now know that I need to buy the correct proportioning valve and distribution block for the disc and drum setup my car now has. Not sure yet if I need the brake junction valve located on the frame rail but I will look into that further My brake pipes are a mix of copper and steel so also need to get the copper ones changed. Thanks for your help and I will let you all know how I get on when I have made the changes needed.

 

[70Barracuda]

Buy the valve from ramman. They will tell you where to get good lines. Do not buy inlinetube.

 

[Billshemi]

You might need more vacuum if the car has after market cam 14 16 inches vacuum

 

[aussiemark]

Being in the UK you will be better off having new brake lines made up locally just copy the original loops and use the protective spring covering (I've seen it for sale on Ebay)

 

[challenger6pak]

It could be as simple as the check valve on the brake booster.