Brake Questions

[Pat Buzzard]

OK this is my stupid question for the month of May (I'm told I only get one per month): What is the correct name for the little ring\bushing thingies that connect the brake disc to the wheel? I think mine need replacement as there is substantial amount of up and down\side to side play in the right front disc (the left front is fine)

[OoPEZoO]

The word you are looking for is brake rotor Bobbins.

 

Check out Motobins. They are out of the UK, but sell aftermarket stainless steel replacements that are well worth it. I think it actually ends up being cheaper than buying BMW replacements and they are a MUCH better product.

[dirtrider]

Morning Pat

 

As mentioned by Keith most of us refer to little spools as bobbins.

 

BMW actually calls them "Roll Pins" & they are $3.81 each from BMW with an additional dollar per roll pin for the needed washer & lock ring required.

 

A little movement in the outer rotor disk to the inner star is pretty normal & won't hurt anything (that is how the rotor floats). If they are rattling then you probably have too much wear.

 

It sounds like your left disk might be a bit tight (should have a bit of movement) so it might have some corrosion or dirt in the rollers. Maybe try a bit of WD-40 in & on the L/H rollers while grabbing the disk & trying to move it. Once you have it free then thoroughly wash the excess WD-40 out with some brake clean then soap & water (don't get brake clean on the wheel paint).

 

[99RT-P]

The bobbins on my front rotors are completely shot...the soft alloy is pretty well mangled on most of the bobbins, and one bobbin is completely gone. Needless to say, there's a LOT of rattling going on with my front brake rotors. The last (only) time I replaced the bobbins was with the BMW OEM parts; that was 69000 miles ago.

 

I've read good things about the Motobins stainless bobbins:

Check out Motobins. They are out of the UK, but sell aftermarket stainless steel replacements that are well worth it. I think it actually ends up being cheaper than buying BMW replacements and they are a MUCH better product.

Last month the Motobins site still showed the bobbin kit, but with a note that they were out of stock and weren't available even for back-order. I checked the site today, and the kit isn't listed at all...completely gone. Does anyone know the story behind this? Or has the kit been moved on the site and I'm just looking in the wrong spot? As popular as the kits seem to be, you'd think they'd still be available.

 

Thanks for any info.

[philbytx]

HERE is the listing for the front brake rotors on Motobins, which includes new bobbins.

They are definitely not showing the bobbins as a separate item. I suggest you call them directly to ascertain the reason they are not stocking them. Prolly PI lawyers involved !!

 

 

[99RT-P]

Thanks Phil. I just wanted to make sure I wasn't missing something on their web site. It's been known to happen to me from time to time.

 

My back-up plan is to order a new set of Grimeca rotors...as you mentioned, that set includes new bobbins. I just wonder if those bobbins are stainless or the softer alloy material? I'll have to look into that. My front rotors are original, with 154000 miles on them. They're almost down to the minimum wear limit, so they don't owe me anything. If I get new rotors/bobbins/pads, I don't have to worry about the front brakes for a long time.

[philbytx]

Jim,

I do believe the Grimeca rotors come with the "better" bobbins.

Time for new rotors mate LOL!

 

[David R]

I could not find the bobbins either.

 

Thanks for the info.

 

David

[SKYGZR]

My back-up plan is to order a new set of Grimeca rotors

 

You may also consider EBC rotors, they have an exclusive "non round" "bobbin" fitment system. SD stands for SQUARE DRIVE

All conventional floating brake rotors use a circular rivet to attach the rotor blade to the inner hub. The SD-SystemTM uses a square sided rivet with many advantages. More Here: Square Drive