I completely borked a wheel cylinder last night. Vice grips, heat, oil, nothing would pull the bleeder screw. Ended up with it so destroyed that I took my bench grinder to it and then drilled it out to 5/16" Still couldn't get an extractor to pull it or even get any threads loosened up. I know I need to tap it to 3/8-24 but what tap should I be using for this? I don't know how to get the correct flare angle for the bottom? And how can I prevent wiping the existing threads and ending up with a worthless/leaky bleeder? This wheel cylinder is over $100 so I thought I'd at least try and fix it before ordering a new one.
I think you may already be to the point of no return. It would be near impossible to tap the bleeder hole to the bottom and not damage the flare seat. I'd try to look for the cheapest replacement, and not waste anymore time or money on that one.
There is potentially a sane repair option...Dorman and others sell bleeder repairs advertised to use only normal tap and drill sizes. These things are basically a threaded sleeve that goes into the drilled out cylinder with center of sleeve set with proper seat and threads for the bleeder supplied with it. Just checked my memor on that on Amazon and they still exist at 6-10 bucks. I have never actually used one of these but they look like an easy repair job. (more tech...I have a set of bleeder "knocker" sockets from I think KD. These sockets fit the hex on the bleeder and contain a shoulder that seats against the top of the hex so you can hammer the things a bit before trying to turn them out. Oh, the joys of salted roads...)
I would go buy a cheap tap, start tapping the hole, when you get a few threads at the top, back the tap out and grind off all but about a 1/2 a thread of the lead angle, then tap down to the bottom. I've done this many times in a blind hole with good results.
http://www.levineautoparts.com/bleederrepair.html Look around you may be able to find it elsewhere but all hope is not lost
Pretty sure most parts stores sell bleeders with self tapping threads...like over sized oil drain plugs... Sent from my DROID device using the TJJ mobile app
I'm striking out on this one, but the oversized brake bleeder repair kits from Dorman look like exactly what I need. I'll pick one up tonight and then try to find the ***ociated taps/drill bits that I need. Thanks, guys!
I don't think repairing this is as extreme as it is being made out to be ... Here is what I think you need, with prices, from McMaster-Carr. 26035A253 Carbon Steel Hand Tap 3/8"-24, 4 Flute, Bottoming $3.14 3474A17 Left-Hand Cobalt Steel Maintenance Length Bit 135 Deg, 1/4" Sz, 3-5/16" L O'all, 1.6" Drill Depth $5.71 2901A161 Gen Purp Black-Oxide HSS Jobbers' Drill Bit Size Q, 4-3/4" Oal, 2.9" Drill Depth, 135 Deg Point $5.34 And, of course, you would need the 3/8-24 bleeder. You can try the reverse-twist drill bit first. It might spin the old screw out. Then, if that doesn't work, move on to the drill and tap. Make sure you are nice and perpendicular. Use a drill press if possible. With both drills, try really hard not to disturb the bottom of the hole, so you don't affect sealing. Of course, there is no guarantee that it will seal, if the old screw galled the bottom surface of the hole, where the bleeder screw seals. It may be possible to redrill that, but I don't know the proper angle.
I have some bleeder screw inserts that I got from Wilwood. They are 1/8 pipe br*** plugs with a bleeder screw. They use these on their alu brake calipers and most good racer supply shops will have them.
It's BRAKES. Pony up the C-note and get on with life. Your life and the people in front of you are worth way way more than 100 bucks.
$100 a wheel cylinder? What's this cylinder off of? Even then as High speed said your life and everyone elses around you is wort more than that too. Would hate to think that you could cost thousands of dollars in damages and maybe funeral expenses all because u save 100bucks...
Agreed. What kind of car is it for? If you let everybody know, perhaps the interchange/subs***ution gods will shine upon you.
Two things you should never try to put a band-aid on for a repair, brakes and steering. Spend the $100.00 your life is worth it.
While the part probably can be fixed, unless a replacement is really expensive, or you have the tools and equipment to do it correctly yourself, it's not worth doing. If the hole isn't accurately drilled and tapped using a mill or a high quality drill press the odds of the new bleed screw sealing are minimal. Even then, you may need to remachine the area where the bleeder seats. You should have a both a starting or plug tap AND a bottoming tap to rethread the hole.
Anybody bother to look at that link I posted? 8.00 and a regular pipe tap is all you need. Its been a while but they actually used to stock wheel cylinder hones and rebuild kits.
yes , i did look at it.... it just may be the thing to fix a rare and hard to find wheel cylinder that's why i want to know what car , it may be a cheap and easy to find
Bleeder screws are the dumbest thing ever. Tiny 5/16 flats with a hole in it - what better way to ensure its failure. If you don't round it off or somehow manage to get a good bite on it will break. Brilliant. I'm surprised some hot fodder hadn't invented something better yet. Banjo bolts is the best thing to happen to brake hoses.
Provided the casting has enough material I think your suggestion is a good one. Because others want to post their opinion is nothing personal against you or your idea. There are some here who would not hesitate to drill that hole with a hand drill and run a tap in at whatever angle it catches. If that happens, at least you tried to help. The guy was talking about going to an oversize bleeder. I gave him an idea of what5 it would entail to do that correctly. About the piece you suggested; You would want more than a couple threads of engagement. With that in mind, I'm not sure the hole could be tapped deep enough using just a "regular" pipe tap. I am thinking that(of course depending on the tap) at the very least the end of the tap would need t*******/shortening to get enough threads in the hole.
I live in one of the worst areas in North America for rusty cars. I work with brakes everyday, there aren't many bleeders I can't get out, the ones I can't get are rusted so bad that they are just a point sticking out of the cyl. then the cyl. gets replaced. On the other hand, if they don't come out quickly, I don't waste a lot of time messing with them just replace the cyl.
It's a 48 Chevy 1-ton truck. Rear bakes. I was going to pick up the repair kit that uses the pipe fitting and the appropriate taps, but I figured I'd try to save what I had first. Here's where I'm at: I drilled out the broken bleeder screw to 21/64" (progressively, and with a drill press) and figured it was worth trying to tap at 3/8-24. Once I drilled it out, the flared end of the old fitting fell right out. I was pretty damn close to dead center and I didn't hit the existing flare seat (due to the old bleeder screw being in the way.) The 3/8-24 tap I had was apparently complete garbage as it didn't go in very cleanly, but eventually I was able to cut threads (or possibly even re-tapped the old threads.) I didn't have a bottoming tap but I was able to cut enough threads to get a regular bolt in there, threaded that all the way down and then finished by tightening a speed bleeder in there. Here's my issue -- I've only got a speed bleeder to put in there. I can't figure out a way to see if it's holding pressure. It does thread all the way in until it's TIGHT. I can hook vacuum up to it but it won't open the speed bleeder even when I handy-vac it up to 25psi. Therefore, I can't tell if it's sealing or not. I'm going to try and rig up a fitting with my air compressor to see if I can force air through. I'll report back.
I'm aware of that. But if I can make it fail at 125psi it will save me the chore of putting it all back together, pumping the brakes and finding out that it's leaking like crazy.
Napa shows rear wheel cylinders for a 1948 chevy 1 ton truck at $129 each so i guess it's worth fixing you old ones
Yeah, might be hard to find one of those. Edit,, according to 36-3window they are available but pricey.
Still alive, boys! With the wheel cylinder secured in a vise my test was inconclusive. It didn't seem to leak from anywhere but my air fitting. Guess it's going to have to be put together and see if it holds hydraulic pressure. I just don't see any other way to test it. And for all the safety czars on here -- I'm doing my best to be safe. I want this truck to stop just as bad as you do. Remember: I'm the one that's driving it!
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