Hydroboost advice

[Archialfa]

I'm in the middle of restoring my 70 Challenger and I need to make a decision regarding brakes.

It was a manual brakes car so I bought MBM front disc brake conversion kit with 12" rotors.

http://mbmbrakes.com/dbk6272-bb-1962-1972-mopar-b-body-e-body-stock-height-12-rotor-disc-brake-conversion-kit/

Nothing has been mounted on the car since the bodywork is now done and it's going to be painted in the next few weeks.

I'm thinking of getting rear disc brakes, too, since it would look lame to have 18" wheels (I already bought Torq Thrust II) and drum brakes. Plus, why spend $$$ on restoring drum brakes when I can add a bit more and buy discs?

What bothers me is the vacuum and have heard from other members of this forum that getting a hydroboost would be the best solution for braking. So, I'm looking at Hydratech stuff:
http://www.hydratechbraking.com/Mopar_E_Body.html

Problem is that I have no clue what part number I need. There are 3 which are listed as "This model for use with vehicles equipped with factory manual brakes" - #3074, 3574 and 3674.

Does anyone have an idea what should I get?

[GoodysGotaCuda]

Have you considered keeping it manual?

I run manual Wilwoods and they work pretty well.


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[Archialfa]

Have you considered keeping it manual?

I run manual Wilwoods and they work pretty well.


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Not really. I like power brakes. Manual steering I can live with, but brakes not really.

[jordan]

Hi Marin,

      I looked at the Hydratech website.  It looks like the difference between the part numbers is dependent on which type of master cylinder you plan on using.  I used the modern style Mopar master cylinder with plastic reservoir.  It seems like you have the option of two different GM master cylinders, one being long rod and one being short rod style.  I see a Wilwood master cylinder that is GM style as an option.  I think it all depends on how you want it to look and what option you want to use for the master cylinder.  You may want to verify with Hydratech before you spend the money. 
     I still love the way mine works and it has never given me any issues.  Some of the best money I spent on my project.  The braking feel and power is just awesome.  Totally modern car feeling. 

Jordan

[7212Mopar]

Jordan is right and depends if your car had original manual brake. I also went with the Mopar plastic cylinder in clear. Easy to find parts or replacement later. You will need to bench bleed the master cylinder. I did that and still took a few more times to get all the air out. It works great except when car is on idle, sometime it has less assist.  Once engine is around a 1000 RPM then it is normal. It could be due to my Bogeson steering box.

[Archialfa]

With the front disc brakes kit I also bought master cylinder and booster:

http://mbmbrakes.com/bck8536-2-mopar-1971-1974-b-body-1970-1974-e-body-booster-conversion-kit/

Does this help to determine what to buy?

I've sent an email to Hydratech too. Let's see what they reply.


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[7212Mopar]

You don't need the vacuum booster anymore going with Hydratech. Just let them know your car had original manual brake and if you want or not want to retain the manual brake bracket. Next would be pick the finish you want with the kit and your preferred master cylinder style. With 18" wheels, you can check out Dr Diff front and rear brake kits. I went with his 13" front and 12" back kits.  11" or 12" rotor looks funny with big wheels.

[jordan]

I think that the old style master cylinder will not work.  You will need a modern style of master cylinder.  You have to choose GM or Mopar style.  And you will not need that big old booster anymore.  The system hooks up directly to the pedal with no factory linkage.  I remember that it was easy to adjust.  I thought the hydraulic power de-aired the system and it would self bleed its self as it ran. 
   I find my brakes work just fine at low RPM.  They still have plenty of boost but are not overly sensitive.  I don't remember driving my car with no power, so I don't know how they actually feel when you loose engine power. 

[Chryco Psycho]

I believe you can just order a unit from Rock Auto , Chev seems to be the cheapest units available through them

[dave73]

I believe you can just order a unit from Rock Auto , Chev seems to be the cheapest units available through them

Interesting. Do you have a part # or year/make/model to search that would work?

[moparcar]

The most common boost unit is from a Chevy Astro Van. Some also use the ones off of late model Mustangs as well. The Astro Van one's are cheap on Rockauto.

The hard part is the adapter plate. Tallon Hydraulics used to sell these separately (not sure if they are still around?) and also a guy on eBay makes a steel one that will work.

Then the linkage is more or less some generic parts as I understand it.

I have not done this myself. This is only from research I have done.

[Cudakiller70]

@YellowThumper has done this with a mustang unit IIRC

[YellowThumper]

@YellowThumper has done this with a mustang unit IIRC

Yessir I have. Dont recall what year specifically it was from. One with the huge mod motor. I had power brakes and utilized its mounting position and also the inside the firewall brackets. My way I did have to cut and weld shorter the shaft that connects to brake pedal. This allowed me to only use a 3/4 thick adapter plate. Plate bolts to firewall and the hydroboost mounts to it. 2 hydroboost bolts pilot thru firewall to capture everything solidly. Overall setup is real simple in the scheme of things.
I did a lot of research in junkyards for the hb units. I will say that everyone is the same brand along with being virtually identical. Regardless of brand car or truck they were on. Mustang, Astro van, suburban, chev trucks, ford truck, dodge trucks etc... all the same. Some differences were the EYE to pedal diameters. But firewall to EYE distances were all same lengths. One main difference was for extra heavy trucks. They had larger bolt and housing sizes on the master cylinders.
You will need new custom lines made. Pressure line from (stock) pump goes to hydroboost first (for safety) then second pressure line goes to steering. Both low pressure drains from hydroboost and steering then T into each other with the single line connecting back to pump return.
I went with Mustang version because hb unit is rotated 90deg. This allows me more room for my eventual turbo exhaust. Also the popularity of Mustang makes for cheap and easy replacements.

[Archialfa]

I did a lot of research in junkyards for the hb units. I will say that everyone is the same brand along with being virtually identical. Regardless of brand car or truck they were on. Mustang, Astro van, suburban, chev trucks, ford truck, dodge trucks etc... all the same. Some differences were the EYE to pedal diameters. But firewall to EYE distances were all same lengths. One main difference was for extra heavy trucks. They had larger bolt and housing sizes on the master cylinders.
...
I went with Mustang version because hb unit is rotated 90deg. This allows me more room for my eventual turbo exhaust. Also the popularity of Mustang makes for cheap and easy replacements.

Does this mean I can use something from European cars? I live in Central Europe so getting something from an Audi, BMW, VW, Fiat is very simple.