Observations from Inspection I

[mhughett]

I picked up my M coupe from it's Inspection I today. Fortunately, I was able to time it such that I got it done a month before the free service ended. There was never a doubt that they knew that this service included the valve adjustment. For good measure, I had them fill out the valve adjustment worksheet that I saw on this site that showed which valves required different shims. The service advisor had never seen this form before and said they are not required to do anything like that for BMW but he was nice enough to have the tech fill it out at my request.

What I found unusual is that 15 of the 24 valves required a different shim. They usually increased the shim size from 2.32mm to 2.36mm or from 2.36mm to 2.4mm. All I know is that the engine seems to run very smoothly now. I thought it ran fine before but it sounds great. The SA also took a picture of my engine with the valve cover off and said it was the cleanest one he'd ever seen. Probably has a lot to do with my 5k oil change intervals.
On a related note, the oil was NOT over-filled (I checked).

I also had them install new Michelin Pilot Super Sports that I bought at Discount Tire a few months ago. I'm anxious to see how they are but with colder weather ahead, they may not get much of a workout for a while.

Finally, I had them check my rotors (again) as I started getting some shimmy when braking from high speeds. This isn't the first time this has happened. They have always put new rotors and pads (free of charge) but this time, the service advisor said he suspects the runout (.003" on one side, .002" on the other) was caused by excessive heat as he saw some blueing in their color. I find this hard to believe since I only had it 1.5 days at the track back in September and it was fine after I got back from there. It only started the pulsating in the last few weeks. He said BMW would probably not cover any more rotor replacements and he recommended I look into a Stop-Tech big brake kit as an alternative. I don't see how they can blame the runout on such light track usage and very mild use during my daily commute. I'm thinking that maybe I should:

1. Go for the Stop-Tech kit,
2. Try a different pad to see if it works with the factory rotors, or
3. Just stay with the factory pads and rotors and hope for better results this time.


What do you think? I think it would be cool to get the Stop-Tech kit but I wonder if it's worth the money invested. For those that have it, how do you like them?

[Finnegan]

Sounds like a pretty good dealership! That's a lot of shimming. I'll bet it sounds better!

I'm not surprised they didn't go for the rotor replacement if you've already had one done. (I take it there's been more than one, which is impressive BTW, this dealership has gone to bat for you.) BMW is pretty strict on warranty replacements, and two or more sets are going to raise some red flags at corporate.

As for the pulsation, well, it could be they're warped, although with floating rotors it's unlikely. More likely it's just uneven pad deposits, particularly if you got the brakes really hot which does a number on the pads which may be pretty well cooked. IIRC, if that happens, the pad just isn't the same and starts leaving more uneven deposits (I could be wrong on this). IDK, maybe try a few bedding procedure passes and see if that clears it up, or just bite the bullet and get better pads and bed those in well.

As for the BBK, if you're getting faster at the track, I'd just swap out the stock pads for something better. I've never run stock pads, started out with Stoptech Street performance (good up to "medium" use on the track). As I get faster I'll look at Hawk DTC-60s or something along that line. As The Hack and a few others have said, the stock rotors damn good, but the stock pads aren't really up to serious track work. Lots of threads already here on alternatives.

If you're interested in the Stoptechs, I'd look at this thread. If you're not wedded to the 6 pot fronts, you might be able to work a deal! But honestly, I'm not saying you need these.

[Uncle Russ]

I just had Inspection I done as well. My Roadie required many shims, too. Was running like crap prior to the adjustment, amazed at what a difference it made.

[inTgr8r]

Originally Posted by Finnegan

Sounds like a pretty good dealership! That's a lot of shimming. I'll bet it sounds better!

I'm not surprised they didn't go for the rotor replacement if you've already had one done. (I take it there's been more than one, which is impressive BTW, this dealership has gone to bat for you.) BMW is pretty strict on warranty replacements, and two or more sets are going to raise some red flags at corporate.

As for the pulsation, well, it could be they're warped, although with floating rotors it's unlikely. More likely it's just uneven pad deposits, particularly if you got the brakes really hot which does a number on the pads which may be pretty well cooked. IIRC, if that happens, the pad just isn't the same and starts leaving more uneven deposits (I could be wrong on this). IDK, maybe try a few bedding procedure passes and see if that clears it up, or just bite the bullet and get better pads and bed those in well.

As for the BBK, if you're getting faster at the track, I'd just swap out the stock pads for something better. I've never run stock pads, started out with Stoptech Street performance (good up to "medium" use on the track). As I get faster I'll look at Hawk DTC-60s or something along that line. As The Hack and a few others have said, the stock rotors damn good, but the stock pads aren't really up to serious track work. Lots of threads already here on alternatives.

If you're interested in the Stoptechs, I'd look at this thread. If you're not wedded to the 6 pot fronts, you might be able to work a deal! But honestly, I'm not saying you need these.

^WHS
Pad deposit is the usual suspect.
It will often happen on track days if you aren't careful about cool down procedure.
Pad deposit usually happens just as you are coming to a stop with brakes applied (stationary hot rotor disc & the pad sticks)

FWIW my procedure is;
A cool down lap at a speed that I use zero brakes.
In the pits I don't use my brakes at all when coming to a stop.
I try to coast in as slow as possible & use the hand brake (with button held in) to come to a complete stop.
Just as I stop I shut it off in gear & release the hand brake.

re the Stoptechs, I have them & love them but would not have considered them if I wasn't planning to keep the car for a very long time.
That said, they are usually easy to resell, just keep your old brakes to put back on.

There are several threads posted here on the + & - of BBKs

[mhughett]

I truly don't thing the problem is pad deposits. I've bedded in the pads per the Zeckhausen instructions and I also am careful about cool down procedures when I went to the track. Also, the shimmy I got recently didn't happen until about 2 months after I went to the track. It seems to happen more based on mileage rather than the type of driving I do.

The strange thing about this car's brake problem (the previous owner had it too) is that the runout problem occurred several times when there was no track time during the rotor's life. Fact of the matter is my daily commute requires very little braking at all. I'm worried that there is something else wrong with the car that's causing it but the dealer is adamant that they've checked everything else.

[inTgr8r]

Originally Posted by mhughett

I truly don't thing the problem is pad deposits. I've bedded in the pads per the Zeckhausen instructions and I also am careful about cool down procedures when I went to the track. Also, the shimmy I got recently didn't happen until about 2 months after I went to the track. It seems to happen more based on mileage rather than the type of driving I do.

The strange thing about this car's brake problem (the previous owner had it too) is that the runout problem occurred several times when there was no track time during the rotor's life. Fact of the matter is my daily commute requires very little braking at all. I'm worried that there is something else wrong with the car that's causing it but the dealer is adamant that they've checked everything else.

^based on your description I would agree that it doesn't sound like pad deposit.
With all that history it sounds like BMW never really got to the bottom of the problem

IDK...
Just a wild ass guess; maybe bad or sticking slide pins causing uneven loading on the rotor?

[gatorfast]

Inspection I? Get out and drive man!

Anyway, nice to see a dealer perform quality service like this.

[pelerojo]

Thanks for the post. I have my inspection 1 due next year and plan on using the shim log too. It was nice the tech took the photo. My maint ran out long ago so this one will be on my tab.

[Etch52]

Originally Posted by pelerojo

Thanks for the post. I have my inspection 1 due next year and plan on using the shim log too. It was nice the tech took the photo. My maint ran out long ago so this one will be on my tab.

Where would I get a copy of a 'shim log' ?

[Phishman]

How many miles do you have on your car? Isn't that kind of early to get new pads?

[Finnegan]

Originally Posted by mhughett

I truly don't thing the problem is pad deposits. I've bedded in the pads per the Zeckhausen instructions and I also am careful about cool down procedures when I went to the track. Also, the shimmy I got recently didn't happen until about 2 months after I went to the track. It seems to happen more based on mileage rather than the type of driving I do.

The strange thing about this car's brake problem (the previous owner had it too) is that the runout problem occurred several times when there was no track time during the rotor's life. Fact of the matter is my daily commute requires very little braking at all. I'm worried that there is something else wrong with the car that's causing it but the dealer is adamant that they've checked everything else.

Originally Posted by inTgr8r

^based on your description I would agree that it doesn't sound like pad deposit.
With all that history it sounds like BMW never really got to the bottom of the problem

IDK...
Just a wild ass guess; maybe bad or sticking slide pins causing uneven loading on the rotor?

Yep, doesn't sound like a pad problem or deposits. I take it the front brakes aren't discolored and blue? Those do the majority of the work, so if you're going to overheat things, I'd expect to see it more there anyway now that I think a bit more.

inTgr8r has a good guess there. Other possibilities are, however unlikely, the proportioning system, or the DSC getting overly involved if you're running with DSC on (but you'd probably see the light flashing if that's the case). Do you have a scanner? I'm curious if there are any faults that might shed some light.

There are a lot of us here running stock brake setups with a lot of track days. I can think of you, and one other at this point, who have had rotor issues. Point being that this car does well on the track and doesn't tend to cook rotors (especially rear rotors). Like inTgr8r said, I don't think they got to the root cause and simply replaced parts, then attributed it to "track use".

[jmillet]

Originally Posted by Etch52

Where would I get a copy of a 'shim log' ?

Here's a worksheet:
S54 Valve Adjustment Worksheet.pdf

[dazed^]

Wouldn't misaligned pins or some structural problem generally also result in a tendency to steer into a particular direction when braking?

FWIW my brakes also have a slight shudder (always have), and as far as I know my car has not been tracked. The shudder got less after I did some 'extra braking' at speed. It never wanted to go sideways though.

I have just over 25K miles on it.

[mhughett]

Originally Posted by Phishman

How many miles do you have on your car? Isn't that kind of early to get new pads?

The replacement of brakes was all due to the rotor problem. Pads were still like new as they had been replaced before. It's BMW's policy to always put new pads on when they replace the rotors.

I agree with InTgr8r and Finnegan in that I still don't think they have gotten to the source of the problem which makes me nervous about spending $3k on a BBK. Right now with new rotors, new Michelin Pilot SS's and the valve adjustment, it's about as good as it gets.