1. 88_AHB

    88_AHB Well-Known Member

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    Hey everyone,
    I'm currently reinstalling the drivetrain back into my dippy and ran into a clearance issue with the drivers valve cover(mopar performance) and the brake booster.I received this car with no drivetrain at the time.Anyways I thought there might be some people in here that might be running a smaller diameter booster? I also thought to carefully dent the one area of the booster but was afraid to damage it and break its sealing abilities.Any help is much appreciated thanks!
     
  2. Joe12459

    Joe12459 Well-Known Member

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    A lot of people use the K car booster in these cars, for extra clearance for engine swaps.
     
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  3. Duke5A

    Duke5A Well-Known Member

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    K car is an option. I've got a smaller booster in mine from a late model C body with a big block. Just got to be sure whatever you're getting it's a 2-bolt master cylinder and not a four.

    With a small block though you can run those valve covers using the original larger diameter booster. You just have to mill the fins down on the valve cover where it interferes. You'll still be able to get the cover on and off.
     
  4. 88_AHB

    88_AHB Well-Known Member

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    Thanks guys,I found two different parts numbers for boosters on those years of k cars. The car was missing the master and booster along with the drivetrain,so it’s been a big puzzle getting everything back together.Duke you say late c body like a 88-93 dynasty or New Yorker?
     
  5. jasperjacko

    jasperjacko Well-Known Member

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    I have a set of those covers and actually cut the back corner that interferes and welded on a flat plate.
     
  6. jasperjacko

    jasperjacko Well-Known Member

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  7. 88_AHB

    88_AHB Well-Known Member

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    Did any of you have to run the matching k car master cylinder? I got the k car booster and trying to attach the dippy master and it wont bolt flush to the new booster.The rod that sits in the master seems to be a little longer than the old dippy one.I did push it all the way down to make sure it is where it needed to be.
     
  8. BudW

    BudW Moderator Staff Member

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    A few issues here. All FMJ’s got either the large diameter brake booster (like what you have) or no brake booster at all (which might be an option). Finding parts to remove the brake booster is getting more difficult now days – but for most of us, I would stick with power brakes.

    Now with that said there are two different versions of brake master cylinders and large diameter boosters. Those with 4-bolt cast iron master cylinders and those with 2-bolt aluminum master cylinders. I’m not sure when the change was made (‘78 or 79) but the 2-bolt aluminum master cylinders are significantly lighter and smaller and is recommended if you have to replace both parts (on an older F or M body).

    4-bolt iron master cylinder
    MC Cardone 131627 b.jpg
    2-bolt aluminum master cylinder
    MC Cardone 131822 b.jpg
    The bolt pattern to master brake booster is also different between the two above cylinders.

    Some B-body and C-bodies have a smaller diameter tandem booster that will fit (in both 2 and 4-bolt versions – but they are also about 3-4” (75-100 mm) longer).
    There are two different K-car brake boosters, single and tandem. Both are smaller diameter than FMJ’s use, with the tandem version a bit longer. Both will fit fine and both versions use a 2-bolt aluminum master cylinder. Front wheel drive cars use a different diameter master cylinder piston – so I would recommend staying with an FMJ 2-bolt master cylinder.

    The K-car boosters use metric studs, so a person will need to use metric nuts (4 for firewall and 2 for master cylinder). Many (but not all) reman brake boosters come with new nuts – so that might not be an issue. I “think” the turbocharged cars got the tandem booster – but not exactly sure. Either booster works fine for most FMJ cars.

    I have a reman A1-Cordone Brake booster 54-73172 (tandem) in the garage (bottom-most picture), to install into my first big block car – which has more of a clearance problem than small blocks do. RockAuto.com shows price to be $52.00 (US) plus shipping with the single version (p/n 54-74100) to be less ($49) which is the middle picture. If looking either up, you might have to not use the dash (or a space) in the part number.

    Factory booster (pictures are not to scale)
    BB 3700210 a.jpg
    BB 3700210 b.jpg

    K-car single booster
    BB Cardone 5474100 a.jpg
    BB Cardone 5474100 b.jpg

    K-car tandem (dual) booster
    BB Cardone 5473172 a.jpg
    BB Cardone 5473172 b.jpg
    Note: these apply to most of the ‘80’s front wheel drive cars except for L-body (Omni/Horizon).


    The suggestion to modify your valve cover has merit – but before deciding on which method to do, just keep in mind the rear valve cover bolt is almost impossible to access with the large diameter booster in place and for that reason alone, I recommend replacing the booster instead of modifying your valve cover.
    BudW
     
  9. 88_AHB

    88_AHB Well-Known Member

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    Thanks bud,
    In the last few days I ordered both of the above boosters from a k car.I was curious why would they offer a single and dual booster? I thought maybe for abs?Might of been a early option in these cars?Seems like I should stick with the dual one. Thanks
     
  10. BudW

    BudW Moderator Staff Member

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    As mentioned above, the K master cylinders have a different diameter piston which will not preform as expected.

    The rods are adjustable. Some cars might need to have master cylinder removed/reinstalled to get the adjustment correct. There is no procedure for this in the FSM (Factory Service Manual) - but there is information about this online.
    BudW
     
  11. BudW

    BudW Moderator Staff Member

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    Turbocharged cars, just because of how they operate, do not generate engine vacuum like naturally aspirated engines do. I also suspect it also might have to do with HD brake option or towing package – maybe.
    I've seen both boosters on naturally aspirated vehicles but only the tandem on turbocharged cars – so not exactly sure why.

    Chrysler didn't start using ABS until '90, I "think", so ABS wasn't an issue on booster size.
    BudW

    Edit:
    By the way, spend a bit of time painting the booster before installing. Otherwise you will have an unsightly rust spot staring at you a short time later. A lot easier to paint before install, than afterwards.

    Also, if painting, take some time to degrease it first, sense paint doesn’t stick to oil.
     
    Last edited: Mar 29, 2019
  12. 88_AHB

    88_AHB Well-Known Member

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    Thanks again I’ll take some acetone or denatured alcohol and wipe it down and paint it. Think I’ll go with the dual booster.
     
  13. Oldiron440

    Oldiron440 Well-Known Member

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    There are adapters to go from 4 bolt to two bolt masters I'm thinking they work with the boosters as well.
     
  14. 88_AHB

    88_AHB Well-Known Member

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    Thanks everyone for the advice/help!
    I used the dual booster for a k car and the dippy master everything bolted together with metric nuts just fine.The only thing i did noticed was, the k car booster rod that attaches to the brake pedal assembly was a little larger diameter hole than the OE dippy one.I might try and see if there's a bushing or something to use to compensate for that or just live with the little bit of slop.
     
  15. Oldiron440

    Oldiron440 Well-Known Member

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    How about a picture of the final install.
     
  16. 88_AHB

    88_AHB Well-Known Member

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    Will do, the cars at a friends house until its derivable again.This car has been a interesting project/challenge missing parts and pieces etc from sitting over the years.I will get a pic of it later in the week.Did paint the booster didn't turn out the prettiest lol! nor is the engine bay planning to clean and paint it up in the future though.
     
  17. BudW

    BudW Moderator Staff Member

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    The slop will not be noticeable – but the clunk noise it will produce, will be irritating.
    A thin plastic bushing (or use of similar firm material) or even using flat stock made into a bushing is also fine). Be sure to apply grease to all sides upon install or you will have a squeak noise (instead of a clunk) on usage - when it should be quiet.
    BudW
     
  18. 88_AHB

    88_AHB Well-Known Member

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    Here's a few pics installed,there's still more to connect/hookup etc before it fires up.
    upload_2019-4-4_18-6-49.jpeg upload_2019-4-4_18-7-11.jpeg
     
  19. Oldiron440

    Oldiron440 Well-Known Member

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  20. 89.Fifth

    89.Fifth Well-Known Member

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    Does changing the booster affect the braking performance or the pedal feel?