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Full Version: UGH Broke my beautiful new Caliper
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mtc911
mad.gif

Got my beautiful calipers from PMB Performance, new pads, rotors, soft lines, the works - everything went great followed their great article on parking brake adjustment...going to wrap it all up and lost grip / slipped somehow whacked the crap out of the bleed valve - broke it clean off all the way at the caliper...nothing to grab to back it out

tried to dimple it and have something to hit on it...no luck

cut a small groove in the little bit of "meat" showing and tried to Hammer drive it out...just fell apart

tried reversing drill bit - it broke off in there -

tried to use different bits and they are doing absolutely nothing against that reversing bit....just basically spinning and not making any depth....

i'm so bummed...the project had gone so well...any ideas? need to get that bleeder valve out of there without destroying this beautiful caliper...
mepstein
@Eric_Shea
Spoke
QUOTE(mepstein @ Jun 8 2019, 07:28 PM) *


agree.gif

I'm sure Eric's been there before.
Chi-town
If a drill bit is broke off in there it's EDM time
porschetub
QUOTE(mtc911 @ Jun 9 2019, 10:19 AM) *

mad.gif

Got my beautiful calipers from PMB Performance, new pads, rotors, soft lines, the works - everything went great followed their great article on parking brake adjustment...going to wrap it all up and lost grip / slipped somehow whacked the crap out of the bleed valve - broke it clean off all the way at the caliper...nothing to grab to back it out

tried to dimple it and have something to hit on it...no luck

cut a small groove in the little bit of "meat" showing and tried to Hammer drive it out...just fell apart

tried reversing drill bit - it broke off in there -

tried to use different bits and they are doing absolutely nothing against that reversing bit....just basically spinning and not making any depth....

i'm so bummed...the project had gone so well...any ideas? need to get that bleeder valve out of there without destroying this beautiful caliper...

If its broken off level with the casting you are basically stuffed really,not to mention a broken drill,I only use very small spanners on the bleed screws what ever size,so I would reach back to PMB and I'am sure Eric has seen this 1000 times,good luck.
lierofox
A tungsten carbide burr in a dremel or other rotary tool is about all you can do to remove a damaged drill bit. It's about the only thing hard enough.

That said if you manage to break off the carbide, then you're REALLY in a pickle.

Superhawk996
Send back to PMB. At this point EDM is the only hope.
barefoot
If there isn't much of that broken drill in there perhaps you can heat it up and let it slow cool to destroy the hardness, then try other drills ??
IronHillRestorations
Next time step back take a breath, regroup, and use one of these.Click to view attachment

Don't mean to sound mean or rude, but realistically if you don't have what it takes to get out the broken bleeder, you definitely don't have what it takes to get out a broken drill bit. Take your lumps and send it back to PMB for an exchange.
914forme
Perry, is not being rude, but I would like to say, a reverse direction drill as mentioned above is touted by industry (cheap Chinese tool sellers) to take these problems and magically make them go away.

av-943.gif

It does work if you have a mill, and can revers the direction and buy quality tooling for it. If these are anything sold on the street corner, it will not work. Best case, they get dull before you do damage, worse case they are hardened to the point they become shatter machines and break off in the item being drilled. BTW, same thing can happen with your tooling for the Mill, the cheap stuff flies around the shop like a missile seeking uncovered eyes to lodge in.

From the start, not sure how you broke it, but bleeders are not meant to take huge force to seat and seal.

Eric is the guy I would send it to. EDM is the process it will take, most likely but worth the professional opinion.

chalk it up to a learning experience, and move on. At least your not asking how do I remove a broken ___________ out of some unattainable part. That is when it becomes a real headbang.gif But still solvable.
DRPHIL914
QUOTE(Spoke @ Jun 8 2019, 11:29 PM) *

QUOTE(mepstein @ Jun 8 2019, 07:28 PM) *


agree.gif

I'm sure Eric's been there before.

I did this on one and Eric sent me a replacement and took mine back. I think I just broke off the bleeder and couldn’t get that out, be he had me send it back.

BTW those look awesome!

mtc911
QUOTE(IronHillRestorations @ Jun 9 2019, 06:43 AM) *

Next time step back take a breath, regroup, and use one of these.Click to view attachment

Don't mean to sound mean or rude, but realistically if you don't have what it takes to get out the broken bleeder, you definitely don't have what it takes to get out a broken drill bit. Take your lumps and send it back to PMB for an exchange.



Thanks all a yup those bits are exactly what I used - unfortunately they didn’t do the trick.
ConeDodger
Erc is at WCR with Diane. I’d guess the soonest you’d hear from him would be Tuesday. Bleeder screws are delicate things. You’ll never forget that. sad.gif
rudedude
If you are in Atlanta there must be many machine shops that have edm capability to remove broken pieces. Doesn't take them very long to do either.
IronHillRestorations
Must've taken a pretty good whack and swaged it in. Regardless of all the opinions, it still stinks. I feel for you brother.
Superhawk996
QUOTE(mtc911 @ Jun 9 2019, 11:04 AM) *


Click to view attachment


Thanks all a yup those bits are exactly what I used - unfortunately they didn’t do the trick.



Not a huge fan of these.
1) the wedge design forces the broken bleeder threads out into the caliper body threads the deeper it digs which ends up working against you.
2) When it breaks off inside the bleeder - now you need to EDM to get the hardened extractor out. I've tried drilling these in a vertical mill with a single point carbide drill. If you're really lucky you can get the drill started on center . . . rarely happens. mad.gif

We all get backed in a corner sometimes and end up in worse situations. Just learn when to give in and EDM before the situation gets worse.

In my experience the only time these simple extractors work is if you have a soft bolt that was simply over tigtened and the head shears off. This releases the stretch of the bolt and there is no longer any load on it. Then it will back out with one of these extractors.

However, a bleeder bottoms in the caliper and now the stretch of the bleeder is still present in the threads of the bleeder even though the portion with the wrench flats has snapped off. It can take a lot more force (i.e. torque) to extract than these small sizes of these extractors can handle. Snap goes the hardened extractor ! Much swearing follows. headbang.gif

Eric_Shea
agree.gif with my fellow Michigander. While this should have worked on a new bleeder, the M7x1 bleeder (7x1 fasteners in general) is too small for those to be effective. Once you get the pilot drilled, the small (generally the smallest in the picture) ez-out will snap right off inside the pilot hole. There's "never" enough strength to overcome the seized M7 fastener/bleeder.

Couple of options:

1. Try a local machinist and see if they're confident. As mentioned above, with a hardened bit in there, I'd say no go.

2. Search EDM in your area. Explain what you have. "Most" won't want to help you.

3. Send it to "Jim's Tap Extraction" in Torrence, CA. (Google). Jim Durish is the best.

4. Send it back here for a new, plated back 1/2 @ $40.00 plus around 1/2 hour of labor.

I feel for ya. Broken bleeders are a bitch with these smaller 7x1's. We see it a lot This is why we tell people to remove them when sending cores in.
mtc911
QUOTE(Eric_Shea @ Jun 10 2019, 09:14 AM) *

agree.gif with my fellow Michigander. While this should have worked on a new bleeder, the M7x1 bleeder (7x1 fasteners in general) is too small for those to be effective. Once you get the pilot drilled, the small (generally the smallest in the picture) ez-out will snap right off inside the pilot hole. There's "never" enough strength to overcome the seized M7 fastener/bleeder.

Couple of options:

1. Try a local machinist and see if they're confident. As mentioned above, with a hardened bit in there, I'd say no go.

2. Search EDM in your area. Explain what you have. "Most" won't want to help you.

3. Send it to "Jim's Tap Extraction" in Torrence, CA. (Google). Jim Durish is the best.

4. Send it back here for a new, plated back 1/2 @ $40.00 plus around 1/2 hour of labor.

I feel for ya. Broken bleeders are a bitch with these smaller 7x1's. We see it a lot This is why we tell people to remove them when sending cores in.



On it's way back to you today...thanks for the help...hopefully i didn't screw it up too badly trying to get it out...
rjames
QUOTE(IronHillRestorations @ Jun 9 2019, 10:07 AM) *

Must've taken a pretty good whack and swaged it in. Regardless of all the opinions, it still stinks. I feel for you brother.


Broke my bleeder off on a reconditioned set of PMB brakes when tightening it after bleeding. Luckily it was a lower bleeder and I had the air out of the system.
I’m 99% positive I didn’t over tighten it. It was a re- conditioned bleeder that was likely already stressed. I’m betting yours was also a reconditioned used bleeder.

When it comes time to bleed the brakes again I will only use new bleeders.
Spoke
I've never heard of EDM. Looked it up and Electrical discharge machining came back. If this is it, how is EDM used in this case?
mtc911
QUOTE(rjames @ Jun 10 2019, 11:50 AM) *

QUOTE(IronHillRestorations @ Jun 9 2019, 10:07 AM) *

Must've taken a pretty good whack and swaged it in. Regardless of all the opinions, it still stinks. I feel for you brother.


Broke my bleeder off on a reconditioned set of PMB brakes when tightening it after bleeding. Luckily it was a lower bleeder and I had the air out of the system.
I’m 99% positive I didn’t over tighten it. It was a re- conditioned bleeder that was likely already stressed. I’m betting yours was also a reconditioned used bleeder.

When it comes time to bleed the brakes again I will only use new bleeders.



Yeah, this one wasn't overtightened either...i accidentally hit it really hard when my tool slipped off trying to reattach the parking brake cable....it was a brand new "speed bleeder" from Pelican....really don't think it was the fault of the bleeder...it was on me for not being more careful around it Mine was the bottom one too - i probably could have left it...but i couldn't live with that
lierofox
QUOTE(Spoke @ Jun 10 2019, 11:01 AM) *

I've never heard of EDM. Looked it up and Electrical discharge machining came back. If this is it, how is EDM used in this case?


It erodes/ablates the metal away using a series of electrical arcs in a manner similar to how electrical contacts in switches and such wear out over time, just done in a more precise and rapid manner.

https://www.youtube.com/watch?v=rpHYBz7ToII Applied Science on YouTube did a pretty in-depth video on it from an amateur's perspective.


https://www.youtube.com/watch?v=rpHYBz7ToII
Superhawk996
QUOTE(Spoke @ Jun 10 2019, 02:01 PM) *

I've never heard of EDM. Looked it up and Electrical discharge machining came back. If this is it, how is EDM used in this case?


Pretty cool process. Can tear though hardened material. Can machine any shape hole. Can drill tiny, deep bore holes smaller than a drill can do.

The problem is the electrodes have to be machined in some instances (like unique hole shapes). At a minimum they have to be just the right size to burn the damaged bleeder ONLY.

If they aren't careful and skilled in how to setup properly, the EDM can burn out the threads. Doh slap.gif

That is why, as Eric points out, most EDM shops won't be anxious to help unless you pony up serious coin. Eric's proposal is a bargain!
mepstein
agree.gif take Eric’s offer and chalk it up to a learning experience.
nordfisch
Hi,
I ALWAYS drill out torn breather screws.
I own the best affordable rewinders, but they are useless for this job.

Since you messed up nothing and saves much useless cheating.
I Did this more than one time even at calipers made of alloy.

Because: The shaft of the sealing cone has a smaller diameter than the thread. You can drill it off and then scratch out the remaining thread spiral. If the thread is MINOR damaged during drilling, it does not matter. The main thing is that the breather screw fits tightly afterwards.
The thread does not seal, only the cone at the end of the screw.

Click to view attachment

Note: The stem of the sealing cone has a diameter of <maybe> 5.5 mm. Exactly up to this drill diameter should be drilled in several stages (4 mm, 5 mm, 5.5 mm). Before drilling, insert a wire into the screw hole, then you know how deep you can drill at most! For example, Use insulating tape to mark this depth on the drill.
With the 5.5 mm drill you can not actually drill too deep - with the thinner ones already!

When drilling with the <maybe>5.5 mm drill, there will eventually be a small jerk - and the sealing cone 'turns free' because it is torn off.
Therefore, you can't actually drill too deep with the 5.5 mm drill.

Take the diameter at your new breather screw!

The stem of the cone can be taken out / blown / rinsed with brake fluid after removing the thread test.

The picture shows no breather screw from the 914, only similar!

I wish you success

Norbert

- Sorry, I used metric dimensions because I firstly posted this at a German forum -
mtc911
QUOTE(nordfisch @ Jun 11 2019, 02:53 PM) *

Hi,
I ALWAYS drill out torn breather screws.
I own the best affordable rewinders, but they are useless for this job.

Since you messed up nothing and saves much useless cheating.
I Did this more than one time even at calipers made of alloy.

Because: The shaft of the sealing cone has a smaller diameter than the thread. You can drill it off and then scratch out the remaining thread spiral. If the thread is MINOR damaged during drilling, it does not matter. The main thing is that the breather screw fits tightly afterwards.
The thread does not seal, only the cone at the end of the screw.

Click to view attachment

Note: The stem of the sealing cone has a diameter of <maybe> 5.5 mm. Exactly up to this drill diameter should be drilled in several stages (4 mm, 5 mm, 5.5 mm). Before drilling, insert a wire into the screw hole, then you know how deep you can drill at most! For example, Use insulating tape to mark this depth on the drill.
With the 5.5 mm drill you can not actually drill too deep - with the thinner ones already!

When drilling with the <maybe>5.5 mm drill, there will eventually be a small jerk - and the sealing cone 'turns free' because it is torn off.
Therefore, you can't actually drill too deep with the 5.5 mm drill.

Take the diameter at your new breather screw!

The stem of the cone can be taken out / blown / rinsed with brake fluid after removing the thread test.

The picture shows no breather screw from the 914, only similar!

I wish you success

Norbert

- Sorry, I used metric dimensions because I firstly posted this at a German forum -



awesome advice...and great overview...while i hope i NEVER have to deal with this again...i will save this for future...I already shipped them back to PMB - let the experts try to fix my mess Thanks so much for the info...
mtc911
the saga continues for me..the joy of old cars...

Question - The Emergency Brake Return Springs on the calipers - Is there a Passenger Side and Drivers Side spring or are they the same?

Here's why i ask.

Drivers side Caliper doesn't "spring" the E-brake arm into the off position...there is a spring on there but it doesn't actually put any tension to pull the arm back. When comparing to the Passenger side the tension part of the spring is on a different side of the post as well...which leads me to believe there are (2) different springs and maybe this caliper has the wrong on it? There is no way (that i can see) to position that spring to put tension on that arm to the "off" position.

Hopefully this isn't a stupid question...but hey wouldnt be my first.

Thanks!
sixnotfour
to answer your question , yes L & R,,, this pic is ferrari so they are probably opposite..
mtc911
QUOTE(sixnotfour @ Jun 20 2019, 03:23 PM) *

to answer your question , yes L & R,,, this pic is ferrari so they are probably opposite..


Thanks. Yup - PMB shipping me replacement. Good to go.
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