I was certainly surprised.

I replaced my brake pads yesterday. On my last pad & rotor replacement, I re-used (re-glued) the old generation vibration dampener. So, this time I could not get the pads separated from the backing plate. Instead, it was easier to remove the calipers and remove the pads. I did not put them the dampeners back this time. The new pads have weights that act as dampeners.

As I am removing one of the calipers, I notice that some of the thread material is coming off with the caliper bolt. I look inside the caliper and the threads are all gone. The carrier threads are intact. I verified with a local dealer that the calipers have internal threading. I was able to get the specified torque (63 ft lbs) on the caliper. The caliper bolts are fully threaded and are not damaged. Should I be concerned?

A new dealer furnished caliper is $700. Can they be replaced individually (i.e. only the driver's side)? If brake safety is not compromised, I will replace the caliper on my next pad service (Will also be rotor time). I will source a better price on the caliper.


Thanks.

Yes, you should be concerned as loss of threaded area in the caliper. Suggest looking at installing a Helicoil thread insert into the damaged openings... You will end up with steel threads for the bolts to grab onto. You will need to drill out and re-tap the damaged holes, but they sell complete kits to make this an easy fix.





“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

threads. Since I was able to get the torque specified, is that an indication that all is OK?

Just be sure the carrier's are OK, run a thread chaser thru the bolt holes, then blow them out and look carefully with a bright light source. Unfortunately, your butt will be the first to know if the treads were not adequate, so a close inspection now is a worthwhile endeavor..............

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

Do I have to drill an oversize hole? Then I assume that I need a larger caliper to carrier bolt? Is a larger high strength caliper bolt available.

Very simple; yes, you drill the hole to a larger size, but then you run a tap thru the larger hole, threading it to accept the helicoil's outside threads. You then screw in the insert with LocTite on it. When finished, the insert will accept your original stock caliper bolts. I think Helicoil has a video of the process on their website……………

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

quite excellent.

It's a little more expensive, but it is foolproof and doesn't require Loctite. It relies on a proprietary tool that literally expands the bottom threads to lock it in place, and the surface portion has a flange that ensures that it won't go winding down into the newly threaded hole.

I became acquainted with this little gem when I learned about it from Gundo. At the time, I was having loads of fun with my headers and PSE exhaust.

Here is a link to their website: [www.timesert.com]

Regards, Maurice.

Quote
JFP in PA
Yes, you should be concerned as loss of threaded area in the caliper. Suggest looking at installing a Helicoil thread insert into the damaged openings... You will end up with steel threads for the bolts to grab onto. You will need to drill out and re-tap the damaged holes, but they sell complete kits to make this an easy fix.

I'm going to suggest, just saying no to Helicoil inserts on brake calipers--I have a 67 Corvette where some prior owner stripped out the carrier bracket (the caliper holes are not threaded on the 67 Corvette's disk brake calipers), and helicoil inserts have been used. I knew that when I bought the car--a "new" insert was put in about a year before I bought the car.

I had brake issues, and pulled one of the calipers. As luck would have it, I picked the driver side rear and that's where the Helicoil was, on one of the two caliper bolts. Well I could tell when backing it out that the bolt in the helicoil wasn't tight at all. The next 6 hours was a hassle of biblical portions first trying to re-install the bolt as is; didn't work. Went to NAPA and bought a helicoil kit, and figured, "How hard could this be to do right". Well it was a pain in the butt.

Had to remove the old insert--that was tough and on my Corvette, I had access to both ends of the hole and dealing with harder metal than you have on the Brembo aluminum calipers the Porsche has. If the initial insert doesn't work, just be warned getting one out, is difficult. Classic Murphy's law--if you wanted it to stay in forever, it would fall right out. If you want something out, it doesn't cooperate.

The insert was too long for the hole--the excess stuck out and was touching the rotor. Trimmed a new insert, and could not get a good fit so the bolt would start in the insert. Yanked off the rotor (which on a 67 Corvette is riveted and had to drill out), so I could get a better angle on the carrier bolt hole; wrinsed, repeated and did this down to my last of the six included inserts. By now, the parts store is closed, so I convinced myself to "re-tap" the bolt hole. Initially I figured that step is not needed bcause it would have been done, when the helicoil was used the first time (note: on Helicoil, you re-tap the hole and the insert in theory threads into the new threads; and it's an odd size tap size too). Threading a hole isn't rocket science, but you have to be careful that you do it squarely because a botched set of threads and you now have bigger problems.

Well that worked, sort of. The plastic tool twisted off just as I got the last insert seated--that plastic tool works well on the first insert, and progressively gets worse, and by the 6th insert, the tool would twist about 3/4's of a turn before it would actually turn the insert in the hole, eventually snapping off.

And the bolt went in, thank goodness. At some point I will replace the carrier bracket--trouble is on the 67 Corvette you have to tear out the half shaft, spindle and other parts of the rear suspension that exceed my personal skill level. I don't trust the darn insert, plus I never want to go through an all day ordeal like I went through, if the insert that's in there now spins loose. And no, one good bolt won't keep the caliper from shifting under a braking load.

Calipers have a good deal of stress and forces applied to them, so they need to be solidly bolted down. I would look for someone who can repair the carrier you have. Or buy a replacement through a dismantler/junk yard. I suspect you can have the carrier repaired for a reasonable price. BTW, Helicoil kits are abusurdly expensive ($40-$50 for a plastic insert tool that may be a one-time use; my saga, it was). And if the Helicoil doesn't work, you get to have the fun I had.

(edited, now that we have decided the carrier is threaded and the caliper is not).

Current Porsche: PCA Club Coupe 2 of 50

Past: 02 986 S

01 996 Turbo

00 Millenium Coupe

99 996 C2

99 Boxster



Edited 2 time(s). Last edit at 01/15/2011 01:31PM by Paul S.. (view changes)

TimeSert is that they sell a tool with it which insures that you are going in completely square.

Regards, Maurice.

Quote
MauriceonLongIsland
TimeSert is that they sell a tool with it which insures that you are going in completely square.

Regards, Maurice.

Actually, from the video I saw (and I am going to guess it was of the master kit--Helicoil has master kits with metal insert tools too, but I've never seen them in any retail store--used with what looks like a pretty standard thread tapping hand chuck), it is different but not on the insert process. They may be easier to put in since it expands the last three threads, where the helicoil expands the entire insert as you twist the insert tool.

And hopefully the piece being threaded can accept a counter-sink. What is in the "specialty kit from TimeSert, which I am betting is what you'd find in a store. Are they even in stores? I've not seen them here in DFW.

Here, NAPA and one area hardware store carried helicoil and the rest of the autoparts store have some off brand which wasn't in the right thread size for the bolt I had. That's another thing you find out when you go looking. These are not a one size fits various sizes. You have to match to the bolt's thread, and because most things about midyear Corvettes are well documented online, I knew the bolt thread size and type to go after.

And it always is easier on a work bench vs. kneeling down with your head stuck inside the wheel well of a car.

Current Porsche: PCA Club Coupe 2 of 50

Past: 02 986 S

01 996 Turbo

00 Millenium Coupe

99 996 C2

99 Boxster

called a "Tap Guide" and it sits square on the surface of the engine (or part that you are trying to "re-tap") as you turn the tap into the middle of it. As long as the guide remains flush with the surface while you are turning the tap, the threads will be square.

As far as sourcing the Time Serts, the best place to get the exact size you need, etc. is directly from the manufacturer as you can order them on the internet.

As JFP says, there is no "almost right" with these applications if you expect it to hold for the long term (or hold at all).

Regards, Maurice.

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

pad dampeners can be discarded. Can the rear dampeners be discarded too? The new pad design does not have integral weights, as the front do.

... are optional on the front or the rear.
I do not use them at all on my personal car.
They are a hassle for quick pad replacement (on the track).
Most cars don't really need them and will have quiet brakes if everything is torqued down properly.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

pad vibration dampeners.

I have run many thousands of miles now with none and no issues, save that once in a blue moon the brakes (Boxster and Turbo though AFIAK the Turbo brakes are still original) develop a bit of a mild squeal upon light use and I have found giving the brake caliper area a good soaping with the DIY car wash wand soap/wash setting followed by a good rinse corrects this.

I always caution against anyone just jamming the wand tip right up next the brake pistons. Keep the spray back a distance and for the rinse I use the spotless rinse setting which produces a much gentler spray.

BTW, a lightly used car or one that is washed frequently even if the brakes are dried can collect enough stuff to plug the holes in the brake rotors. When I first got my Turbo home I spotted this condition. If your car runs drilled rotors you want to make sure the holes are clear/clean.

Oh, I don't know what MY your car is so you may want to visit a dealership parts department armed with the car's VIN and ask if vibration dampeners have been dropped for your car, just to be sure.

Sincerely,

MarcW.

An improperly installed, or wrong length helicoil, and there was a problem. I'm not at all surprised. These inserts come in many different lengths as well as diameters; I personally have seen people screw up the installation of helicoils in every way possible; wrong size drill used, not drilled straight, wrong tap used, wrong size helicoil used, no LocTite, etc., etc.......... If you do not follow the directions, and/or use the wrong size insert, it isn't going to work very well, if at all. And both the helicoil and timeserts are designed not to be easy to remove, otherwise they could back out all on their own or when the bolt is removed, which is not a good thing. Removal usually involves re-drilling to remove most of the insert thread material, then removing the rest using a special tap. Done correctly, both the helicoil or timeserts are a permanent fix at a reasonable cost. I've used them for more than 30 years on everything from a lawn mower to a Pro Stock race car without incident, and would not hesitate to use them again. In an alloy mount, the insert is actally stronger than the original treads in the alloy.

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein



Edited 3 time(s). Last edit at 01/15/2011 03:37PM by JFP in PA. (view changes)

... NOT threaded.
They can't be, otherwise you could not get them tight enough because you could never align the threads on he caliper with the threads on the wheel carrier.
The only threads are on the bolts and on the wheel carrier.
Sometimes calipers seem to have threads, but that's just the bolt's threads have embossed the paint.

[i83.photobucket.com]

BTW the person in that dealership that gave you that information is totally wrong.

Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna




Edited 1 time(s). Last edit at 01/13/2011 03:48PM by Pedro (Weston, FL). (view changes)

... if you saw thread material on the bolts as they came out, it's from the wheel carrier.
What JFP recommends is to rectify the situation at the wheel carrier, where the threads are.
You don't need new a new caliper.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

this is why you always hand start bolts and use a torque wrench! especially with alloy parts.

Grant

(who's brakes finally stopped squealing)

Quote
grant
this is why you always hand start bolts and use a torque wrench! especially with alloy parts.

Grant

(who's brakes finally stopped squealing)

Best advice in the world--until the day I die, I will never understand how (whoever did it) stripped out the threads on the carrier bracket on my 67 Corvette. I take the bolts out, clean them off with brake-kleen, hit with a wire brush as needed or buy a new bolt if it's bad, and then turn with my fingers to start.

Current Porsche: PCA Club Coupe 2 of 50

Past: 02 986 S

01 996 Turbo

00 Millenium Coupe

99 996 C2

99 Boxster