Home Forums Tech Talk Threaded Bleed Screw Hole

This topic contains 12 replies, has 3 voices, and was last updated by  Timothy Strawkas 2 years, 3 months ago.

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  • #50656

    Robert Fisher
    Participant

    Hello,

     

    After trying to bleed the brakes on my Arrows AX9, I found that one of the two bleed screw holes on the caliper is stripped so the screw won’t go in properly (which is interesting since it’s worked for 3 race weekends like that…). Would it be OK to try and tap new threads (a slightly larger size obviously), or would that be risky. I’d like to not have to spend 350+ on a new caliper. Or, has anybody tried putting a non-Arrows caliper on an AX9 that is perhaps a bit cheaper?

    #50659

    Walt Gifford
    Participant

    That’s an example of something that works but with a decreased safety margin.

    It depends on how much metal you have to work with. MCP has a caliper with brass inserts that hold the bleed screw see link. I would get one of those and install it in your caliper if there’s enough metal to do it. I believe you need a tap for 1/8th pipe thread.

    https://cometkartsales.com/MCP-Brake-Caliper-Parts/

    Or you could drill and tap for the next bolt size and use a bolt with a copper washer. You have to get it square.

    Or you can mail it to me.

    Gif

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

    #50667

    Robert Fisher
    Participant

    Hmm, the bleed hole that’s stripped is on the side where there isn’t much metal around it. I could probably tap a slightly larger size, but not much. I might have to have somebody add some aluminum around this area to stiffen it up so the tapping process doesn’t bulge it out. I might try your MCP idea if the 1/8th isn’t much bigger than the standard screw. (Any idea what the standard screw size is?)

     

    Here’s a crazy idea: could I just seal up this hole for good, and instead of bleeding air at the caliper could I bleed it at the master cylinder?

     

    How much would you charge to fix this yourself?

     

    #50727

    Walt Gifford
    Participant

    If anyone works cheaper in the karting industry let me know I’ve got some work for them. Why don’t you post a pic.

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

    #50743

    Robert Fisher
    Participant

     

    #50744

    Robert Fisher
    Participant

    So, this is probably the cheapest solution possible: I was planning on having somebody reinforcing the blue area right? Turns out that given the lack of rigidity I tapped it with a hammer a bit and now the threads engage the screw’s threads. Perhaps this was the initial problem: not a stripped thread but the area was bulged outward.  It might not be sealed though, I’ll install it in a few days and test it. If I don’t see any leaking from this area, I guess its good for now. I’ll probably get a new caliper soon anyway just to be safe, but assuming this holds a seal I’ll buy that new set of tires that I need first!

    #50751

    Walt Gifford
    Participant

    That thing is toast. Plan on suddenly losing all brake pressure. You can’t really hammer aluminum back and forth it gets crumbly and if it’s striped down in there you’re only grabbing threads at the weak opening. I could maybe tap it deeper but I don’t know if I could cut away enough to get a sealing surface. If you try to put that much aluminum weld on it, it will probably warp badly if it doesn’t melt in half. Designed obsolescence.

    Gif

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

    #50752

    Timothy Strawkas
    Participant
    #50753

    Timothy Strawkas
    Participant

    I just read your last comment again, A “tap ” of the hammer!! really!! and you think its going to hold brake pedal pressure!! AXE IT! I know it hurts but hitting A wall is going to hurt more, or the other person you use as A brake.

    #51115

    Robert Fisher
    Participant

    OK, so my caliper is junk. I’d still like another option other than the arrows caliper though. How about using this bracket: https://cometkartsales.com/Brake-Caliper-Bracket.html

    and using this caliper: https://cometkartsales.com/MCP-1375-SER-Rear-Red-Caliper-with-Pads.html

    Or is this caliper too small?

    #51135

    Timothy Strawkas
    Participant

    This caliper with that bracket would be good. Have to have A 1/4 in rotor also.

    https://cometkartsales.com/MCP-1375-Rear-Caliper-with-Pads.html

    #51138

    Robert Fisher
    Participant

    I like that yours is cheaper, but is there a downside to the one you posted?

    #51141

    Timothy Strawkas
    Participant

    not as fancy, its been the American mainstay caliper for yrs. I’ve never seen anyone use it on TAGs or shifters but I couldn’t see that being much of A problem as long as your not riding the brakes every corner.

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