Bizarre brake situation, how can this happen?

[unpolire]

Recently I gave my 2003 Boxster Tiptronic to an automotive restoration shop that I have used for bodywork in the past. They offer full restoration services, so since I wanted a new top installed and my leather seat bottoms recovered, I also let them install all new brakes and hardware, excluding the calipers, but including the parking brake shoes and hardware. I supplied all of the factory Porsche hardware and sensors along with upgraded black oxide slotted and drilled rotors and carbon ceramic pads. Prior to this the car had been fully serviced by an ex-factory Porsche mechanic who has a thriving shop. He had informed me that my brakes were the originals and I needed the supplied parts replaced.

When I picked up the car from the restorer, I asked if the parking brake was now working and I was assured that the brakes were all working perfectly. I got the car in the evening and drove it home in the dark. I noticed a loud grinding noise coming from the left rear on the drive back, but couldn't stop to analyze it in the dark. The next day I start checking everything and found the front and rear wheels and tires mismounted, with one rear on the left front and the front on the rear! In pulling off the wheels and tires to reposition, I noticed the rotor set screws MISSING from the rotors. Even more alarming was the new groove in the new left rear rotor where it went metal to metal in contact with the rear caliper pin! How could this happen with the wheel clamping the rotor to the hub, even with the set screws missing? Is there something else seriously wrong after they installed the new rotors and parking brake shoes? I'm going to take it all apart but want some guidance as to what could possibly have occurred. The mechanic who did the work has already been fired by the shop as he also didn't close fastners, bleed nipple covers, and the rest of the mistakes.

[Gilles]

Wow at least you didn't loose a wheel on your way home.. thankfully (luckily..?) you are ok.. regardless, it sucks
.

[unpolire]

Originally Posted by Gilles

Wow at least you didn't loose a wheel on your way home.. thankfully (luckily..?) you are ok.. regardless, it sucks
.

Thank you. I'm looking forward to a person familiar with the Boxster rear calipers to enlighten me as to what caused the interference and metal to metal contact. I have not worked on this car mechanically because it's been in the hands of top Porsche professionals for everything until now. The ex-factory Porsche mechanic only installs OEM parts that he procures, so he couldn't perform my performance brakes upgrade.

[Boxstard]

Why don’t you take it back to the shop and let them correct whatever is wrong?

I see many posts like this, one having work done at a shop then trying to figure out what they did wrong and fix them on his own… if one can work on it, why not DYI in the first place?

I guess you don’t feel like going back to them based on such poor job done but hope they make it right for you one way or the other.

[unpolire]

After the cost, time, effort, and trust put into the mechanical repairs, and their complete lack of competence in an important number of tasks, I cannot allow the restorer to repair the car. All of my metric tools are hundreds of miles away in storage with my large collection of cars. I normally do all maintenance and mechanical repairs on all of my vehicles, but I will usually maintain professional services on a vehicle with only professional service history. The reason for seeking the opinion of one familiar with Boxster rear brakes is so that I can properly correct whatever the restorer has undone. It was simply a matter of convenience, especially during the global pandemic lockdown when the car was delivered to the shop. I would have done the brskes myself had I any inkling of incompetence. Owners ship their cars and trucks globally to this restorer, so I trusted the " one stop shop" to my detriment. First time ever.

[PLP]

Uhm, I am lost a bit here.

The rotors, at least on mine (also 2003, base) without the set screws would rotate easily on the hub.
There is no way the rotor could touch the caliper.

Only, after the wheel removal, the rotor may become loose and at this point, and this point only, it may contact the caliper.

Sets screws are... not necessary. They are there only to hold the rotor in place during wheel removal/installation. Those screws do not play any role, except convenience factor.
Hence, I would not stress about them this much.

As Boxstard said - if you well know how to do it, why not doing it yourself? I understand time constrains or convenience... but when it comes to brakes - I frankly do not trust shops.
The only time when I allowed someone to do brakes on my car was back in 2008 when I did not have any tools yet (in this country, lol) and I had to trust my mechanic, who was trustworthy.
Since then - I did all brakes myself with proper torque applications, correct cleaning procedures, and lubrication when appropriate (as this one is misunderstood very heavily).

[78F350]

PLP said exactly what I was thinking. Can you post a pic of the grooved rotor and caliper? If the caliper pin scratched the rotor braking surface something is not installed correctly. I wonder if the groove is from debris that got jammed into the new pad?

[unpolire]

[IMG][/IMG]

Originally Posted by 78F350

PLP said exactly what I was thinking. Can you post a pic of the grooved rotor and caliper? If the caliper pin scratched the rotor braking surface something is not installed correctly. I wonder if the groove is from debris that got jammed into the new pad?

[unpolire]

I agree with you 100% and have performed all of my brake jobs on all of my cars for the past 40 years. I trust the ex-factory Porsche mechanic with brakes and regret not having him install OEM pads and rotors when the car was in his shop for full services after sitting dormant for years.

The restorer shop does complex jobs like converting classic Barracudas to Hellcat powertrains with modern ABS and big brake kits, as well as full restoration on classic Mercedes-Benz, Porsches, and VWs. They looked competent. All of my metric tools were hundreds of miles away locked in a container.

The job was done worse than I thought because when cornering, noise from something contacting metal came from the left rear and a deep groove the width and location of one of the caliper pins is in the newly installed rotor after a 35-mile drive. My photo jpegs won't load here and manual attempts did not work. I'll remove the caliper and rotor and determine what has gone horribly wrong. There were no other issues with the car when delivered to the restorer and new tires and an alignment had just been done.

[Boxstard]

Originally Posted by unpolire

I agree with you 100% and have performed all of my brake jobs on all of my cars for the past 40 years. I trust the ex-factory Porsche mechanic with brakes and regret not having him install OEM pads and rotors when the car was in his shop for full services after sitting dormant for years.

The restorer shop does complex jobs like converting classic Barracudas to Hellcat powertrains with modern ABS and big brake kits, as well as full restoration on classic Mercedes-Benz, Porsches, and VWs. They looked competent. All of my metric tools were hundreds of miles away locked in a container.

The job was done worse than I thought because when cornering, noise from something contacting metal came from the left rear and a deep groove the width and location of one of the caliper pins is in the newly installed rotor after a 35-mile drive. My photo jpegs won't load here and manual attempts did not work. I'll remove the caliper and rotor and determine what has gone horribly wrong. There were no other issues with the car when delivered to the restorer and new tires and an alignment had just been done.

Good luck and I trust that you can correct things on your own and enjoy the car in no time.

I just hate to my gut that the shop is getting away with such horrible job, and this reminds me of how I got into wrenching my cars for over 30 years.

My first car was a 72 Beetle back in 1989, and I had a VW dealership do valve gap adjustment. On my way back home, a rear tire came off of the car in the middle of intersection and I somehow managed to avoid accident. They forgot to torque lug bolts properly and I got one lug bolt lost out of them after argument but no sincere apology for potentially killing me, I was just their inconvenience. It was then that I decided to rather spend money on tools and manuals to handle repairs all myself, and basically I’m maintaining and repairing all of my cars ever since, unless the car is under factory warranty. I just started doing wheel alignment home too, while I still have to let a shop mount tires and balance them, but even then I don’t let a shop touch my 986, only bringing them loose wheels as I have two sets of wheels for summer and winter tires.

[unpolire]

Originally Posted by Boxstard

Good luck and I trust that you can correct things on your own and enjoy the car in no time.



I just hate to my gut that the shop is getting away with such horrible job, and this reminds me of how I got into wrenching my cars for over 30 years.



My first car was a 72 Beetle back in 1989, and I had a VW dealership do valve gap adjustment. On my way back home, a rear tire came off of the car in the middle of intersection and I somehow managed to avoid accident. They forgot to torque lug bolts properly and I got one lug bolt lost out of them after argument but no sincere apology for potentially killing me, I was just their inconvenience. It was then that I decided to rather spend money on tools and manuals to handle repairs all myself, and basically I’m maintaining and repairing all of my cars ever since, unless the car is under factory warranty. I just started doing wheel alignment home too, while I still have to let a shop mount tires and balance them, but even then I don’t let a shop touch my 986, only bringing them loose wheels as I have two sets of wheels for summer and winter tires.

My brother took my 1971 914 to a Sears Auto Center for tires or brakes years ago. He pays the bill and pulls onto the freeway and accelerates into traffic. 3 of the 4 wheels and tires fly off of the car, one bouncing directly into the path of an elderly couple, bouncing over their windshield. The car is on the rotors and one wheel still barely attached at the entrance ramp. They had failed to tighten ANY of the wheel bolts! No one died by sheer luck. They paid out thousands in repairs, rental cars, etc.

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[PLP]

Originally Posted by unpolire

They had failed to tighten ANY of the wheel bolts! No one died by sheer luck. They paid out thousands in repairs, rental cars, etc.

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It has never happened to me... yet... but I was wondering.
How in the world one can drive the car long enough and not feel something is wrong with wheels?
I mean, is it possible for the wheel to simply snap off in a fraction of second without any warning? Don't you feel a wobble or something? Noise?
My little brain is unable to comprehend it.

[Boxstard]

Originally Posted by PLP

It has never happened to me... yet... but I was wondering.
How in the world one can drive the car long enough and not feel something is wrong with wheels?
I mean, is it possible for the wheel to simply snap off in a fraction of second without any warning? Don't you feel a wobble or something? Noise?
My little brain is unable to comprehend it.

It can happen fast while you wonder what the heck. In my experience posted earlier, I was just 18 and owned the car for only two months, so freshman when it comes to detecting car issues, but I recall that my rear wheel started to rattle violently and shortly after that the wheel was rolling on its own before I could pull over or anything….

[Boxstard]

Originally Posted by unpolire

My brother took my 1971 914 to a Sears Auto Center for tires or brakes years ago. He pays the bill and pulls onto the freeway and accelerates into traffic. 3 of the 4 wheels and tires fly off of the car, one bouncing directly into the path of an elderly couple, bouncing over their windshield. The car is on the rotors and one wheel still barely attached at the entrance ramp. They had failed to tighten ANY of the wheel bolts! No one died by sheer luck. They paid out thousands in repairs, rental cars, etc.

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OMG that could have been a lot worse!

Actually 914 was my third car since that incident with my bug, the most memorable incident beside blowing up the engine with a dropped valve was when I snapped the throttle cable 90 miles away from home. I re-routed the cable from engine lid through window into the cabin, with a string attached to the broken end of the cable, and operated throttle with my left hand while shifting gear with my right hand. Using all hands and legs to drive the car back all the way home, it was a great excessive and felt like I was really operating a machine!

[unpolire]

Originally Posted by PLP

It has never happened to me... yet... but I was wondering.

How in the world one can drive the car long enough and not feel something is wrong with wheels?

I mean, is it possible for the wheel to simply snap off in a fraction of second without any warning? Don't you feel a wobble or something? Noise?

My little brain is unable to comprehend it.

He didn't get even 100 feet! They flew off as he accelerated after pulling out of the service garage. Located right next to the freeway entrance ramp. I found wheel bolts all over the freeway and roadside when I went to retrieve the car with a flatbed.

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[unpolire]

Figured it out!

The rotors on the car were the factory originals and had reached or passed under the minimum allowed thickness. When the new rotors were installed, contact occurred between the caliper pin and the rotor BECAUSE OF A WORN REAR WHEEL BEARING! There was no contact with the thin rotor, so I had no idea. The car has only been driven about 4,000 miles in the past 3 years, mostly by my son, so I was the only one to drive it after the new rotors and pads, and only for 35 miles.

When carefully cleaning and checking the rotor and caliper I noticed a small amount of radial play from the rotor when grasped. When I tested the tire and wheel after mounting, the movement was much amplified, and I realized what had happened.

[Boxstard]

Originally Posted by unpolire

I found wheel bolts all over the freeway and roadside when I went to retrieve the car with a flatbed.

When that happened on my VW bug, I found 3 lug bolts still captured behind the hub cap but one escaped and could not find it on the road…

[old911doc]

Before you order your bearings, be aware that the S version uses a different bearing, and half shaft, than the standard model Box.

What a mess of a situation you had. I would think that a diligent mechanic would wiggle the hub to check for bearing play, sort of reflexively, while replacing discs and pads. That simple brake service is the first thing that instructors have novices do, well before letting a novice get hold of a spark plug socket.
And, to my mind, a Boxster is a relatively easy car to care for. Lemme tellya about a Lotus Elan…

[old911doc]

Oh, and one last thing, PLP is right, the little setscrews are more a convenience than a necessity, but I would suggest you should indeed use them, so that before you put the tire on you can rotate the disc to check that it is indeed not warped, and so you can check the bearing integrity (!!!). That said, they can certainly cause unnecessary grief by rusting in place, getting the head stripped, etc. So, use them, but with plenty of anti-seize paste, and tighten just ‘finger tight’. The heavy forces of braking are taken by the wheel lug bolts, or on studs ( in the case of…old 911’s…).

[Boxstard]

Originally Posted by old911doc

Oh, and one last thing, PLP is right, the little setscrews are more a convenience than a necessity, but I would suggest you should indeed use them, so that before you put the tire on you can rotate the disc to check that it is indeed not warped, and so you can check the bearing integrity (!!!). That said, they can certainly cause unnecessary grief by rusting in place, getting the head stripped, etc. So, use them, but with plenty of anti-seize paste, and tighten just ‘finger tight’. The heavy forces of braking are taken by the wheel lug bolts, or on studs ( in the case of…old 911’s…).

My impact driver is used almost exclusively for removing those little rotor set screws, works every time even when they got frozen. As noted already, they don’t bear much load so no need to be super tight and if you use anti-seize you will not have issue removing them. That said, they should not be omitted and obviously a shop who does such cannot be professional enough and trustworthy.