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Technical F1 master cylinder help

Discussion in 'The Hokey Ass Message Board' started by novaskilling, Jun 28, 2022.

  1. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    I recently installed a set of 48-52 f1 pedals, crossmember and a new master cylinder in my model A chassis. The brake pedal has to lay so far forward in order for the pushrod to engage the master. I was wondering what brand master cylinder everyone is running? Maybe the one I bought isn’t very good? I got it from a local guy new in box it’s centric.
     
  2. Rock Auto sells Centric so it must be ok.
     
  3. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    thats what i figured, just need to figure out how to get the pushrod and pedal happy. seems my pedal is super far forward with the return spring on it pulls the pedal enough the pushrod comes out of the master.
     
  4. sdluck
    Joined: Sep 19, 2006
    Posts: 2,966

    sdluck
    Member

    That could be a power brake master,the are more shallow then a non power brake. The piston that is.
     

  5. Centric is a good brand. Push rod is adjustable.
     
  6. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    I’ve got the pushrod adjusted to its maximum length. In order for it to rest in the master properly the pedal is laid so far forward. When I attach the return spring the pushrod falls out as it’s too short. I have an oe ford pushrod and aftermarket and both are the same. I’m questioning if the master cylinder is the issue. If it’s too deep and allowing to much of the pushrod to enter?
     
  7. sdluck
    Joined: Sep 19, 2006
    Posts: 2,966

    sdluck
    Member

    Just make a longer push rod for it
     
  8. we need a picture. to many variables. I have run early ford and f1 pedals with the stock pushrod and an adapter to dual reservoir master with no issue. need to see what you are working with.
     
  9. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

  10. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    I posted a couple pictures. As you can see with no return spring the pedal is laid far forward. (I still need to heat and bend it past the block) with the spring attached it corrects the pedal but you can see the pushrod sitting at the very edge of the master bore. This is also fully adjusted to its longest length
     
  11. Is the Master a stock type or late model dual corvette or mustang master? Some of the masters are made with a piston that is drilled for the push rod to go into it. The early fords I have played with if it had the original master, the push rod only went in about 3/8 of an inch. the return spring and dust boot help hold it in place. I have gotten replacement masters that have the origin smaller spot for the push rod and ones drilled like a late model. if you master is drilled, you can use a spacer that slides into bore of the master cylinder to take up the length, speedway probably has them, but I know it comes with most of there master cylinders automatically. If you have the stock type master cylinder, id highly recommend swapping it to a dual master. just way safer.
     
  12. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    Thanks for the reply, so the master is new from rockauto it’s a centric brand. It’s single pot like original. The pushrod goes deep inside the master most of the pushrod goes in before it engages.
     
  13. That's your issue, The easiest way to do it is to make a longer push rod, there are several ways to do this, longer pieces that thread together at the adjustment point on the pushrod is how i would do it, or locate a "bullet" that fits into the master cylinder piston. Either way a good return spring is a must.
     
    alanp561 likes this.
  14. jimvette59
    Joined: Apr 28, 2008
    Posts: 949

    jimvette59
    Member

    Find out why the push rod is deep inside the M/S first. It should not be deep inside the master cylinder. It looks like the master cylinder is not returning to its neutral position or there parts missing. Do you have your brakes bleed and working ? Don't bend the peddle arm. JMO.
     
  15. alanp561
    Joined: Oct 1, 2017
    Posts: 2,429

    alanp561
    ALLIANCE MEMBER

    I moved my master cylinder back about 6". I brought the brake pedal up to where it should be and measured for a longer push rod. Went to my local machine shop and got some hard rod, cut it to length, rounded off the end that goes into the master and threaded the other end for the clevis. Cost me $10. Sorry, no good pictures.
     
  16. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    I figured there might be an issue with the master but I had nothing to compare it too. Man thank you so much for helping solve this!
     
  17. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    Hi the brakes are not bled or plumbed yet. The master does have full travel to return but the shaft for the pushrod to sit in is deep inside the master. It consumes most of the pushrod before engagement occurs
     
  18. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,967

    6sally6
    Member

    Too short of brake push rod is NEVER a good thing!
    You don't realize HOW good until you hit the brake and the rod falls out!!
    Mine attaches to the pedal with the help of a cotter pin to hold it in place.
    Coming home one night I hit the pedal and... cotter pin...washer...everything fell onto my foot (as the pedal fell to the floor!!). Talk about an "empty feeling" in your stomach/groin area!!!!
    Thankfully everybody had gone to bed so there was no traffic.
    New cotter pin was installed with a strip of metallic duct tape wrapped around the pin and pedal arm.
    Yeah......fix-your-rod if it's too short.
    6sally6
    (somebody will REALLY have a great time with my comment!!!!)
     
  19. novaskilling
    Joined: Jul 8, 2018
    Posts: 113

    novaskilling
    Member

    I just measured the rod and it inserts about 1.5” Into the master just to seat. No engagement at that point yet.
     
  20. Yeah you need that bullet or a 1.5 inch longer pushrod
     
  21. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,173

    Doublepumper
    Member
    from WA-OR, USA

    A long rod could potentially cause binding, due to angles and being deep inside the master. Something to check. It may be better to use an adapter to keep the rod shorter.
     

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