Flex Disc Replacement

**organic///M** · 06-07-2007, 08:26 PM

I am planning on replacing the guibo soon. Do I only need to purchase a new guibo, or do I need to purchase new nuts and bolts? If so, specifically what parts? http://www.realoem.com/bmw/showparts...05&hg=26&fg=10

**emro1205** · 06-07-2007, 09:10 PM

I ask the same thing to the service parts guy at the dealer he told me it's better to replace 1 to 6 since it doesn't cost that much.

**Itsablurr** · 06-07-2007, 09:16 PM

What are the symptoms of a failing guibo?

**clintjg** · 06-07-2007, 09:46 PM

First symptom: The drive line will chatter more than normal when on/off acceleration or in/out on the clutch when speeding up or slowing down.

It's easy to check when under the car for cracks or wear etc.

FWIW I reused my bolts.

**SunzOut** · 06-07-2007, 10:13 PM

Visual inspection will show if it needs replaced, look for cracks or splits.

I resused the bolts but got new nuts from BMW dealer. On my M it took about 20 mins. I did not have to remove anything other than the 6 bolts.

**2000Z3M** · 06-08-2007, 05:11 AM

here is a pic of my guibo, it needed to be replaced:

**fmcfad01** · 06-08-2007, 06:53 AM

where is the best place to buy the flex disc/guibo? I have seen them for $75ish...

**SunzOut** · 06-08-2007, 08:49 AM

$75 is a good price. I got mine from OEMbimmerparts

**Itsablurr** · 06-08-2007, 09:39 AM

Why do they fail so often on BMWs, but i never or rarely hear of it on others? Does anyone make a more robust one, or is there something swappable out there?

Most anything BMW does with rubber and something inserted into it seems destined to fail, causing headache, lighter wallets, daycare, etc... I just hope they don't go into the prophylactic industry.

**clintjg** · 06-08-2007, 09:40 AM

Originally Posted by Itsablurr

Most anything BMW does with rubber and something inserted into it seems destined to fail, causing headache, lighter wallets, daycare, etc... I just hope they don't go into the go into the prophylactic industry.

**2kredz3** · 06-08-2007, 10:28 AM

well now that i know what a bad one looks like. . .i will be adding that to my list of mods er up keep.

**xatlas0** · 06-08-2007, 10:47 AM

Originally Posted by Itsablurr

Why do they fail so often on BMWs, but i never or rarely hear of it on others? Does anyone make a more robust one, or is there something swappable out there?

Most anything BMW does with rubber and something inserted into it seems destined to fail, causing headache, lighter wallets, daycare, etc... I just hope they don't go into the prophylactic industry.

Most other manufacturers of high-power cars tend to use single-section driveshafts, with 2 U-joints, instead of the dual-section unit we have, with one U-joint in the middle, encased on the center support bearing.

BMW kinda designed themselves into a hole with it, as the point of the guibo is to absorb drivetrain vibrations and make the car smoother. Making the guibo stronger makes it absorb less, so then it doesn't do what it is supposed to do. Making it absorb more makes it weaker.

In terms of an upgraded guibo, I'm kinda suprised nobody has tried an E39 M5 guibo.

Ah, here's why, the E39 guibo is bigger:
E39 M5: 105mm
http://www.realoem.com/bmw/showparts...88&hg=26&fg=10
S54 Mcoupe: 96mm
http://www.realoem.com/bmw/showparts...05&hg=26&fg=10

I suppose you could switch the transmission output flanges and the guibo-side driveshaft flange.

Alternatively, you can see what cardcounter (over in the FI section) did, since his car uses a very similar driveline. He's got a ~1000rwhp E36 328. I think he ended up going the dual U-joint route, but before that, he rand with an upgraded guibo. (back when he had ~600rwhp)

**fmcfad01** · 06-08-2007, 01:37 PM

is it necessary to replace the centering sleeve, hex bolts, and self locking nuts when you do this replacement (all the hardware that attaches to the flex disc)?

I always use BMW of the Main Line's parts page. They have the flex disc for $80.82...best price I can find currently.

**clintjg** · 06-08-2007, 01:46 PM

Try Circle bmw

**fmcfad01** · 06-08-2007, 02:13 PM

Originally Posted by clintjg

Try Circle bmw

Yeah, but then I have to pay for shipping! BMWOTML is 5 min from my house...i just give John a call and go pick it up!

**Itsablurr** · 06-08-2007, 02:55 PM

Originally Posted by xatlas0

Most other manufacturers of high-power cars tend to use single-section driveshafts, with 2 U-joints, instead of the dual-section unit we have, with one U-joint in the middle, encased on the center support bearing.

BMW kinda designed themselves into a hole with it, as the point of the guibo is to absorb drivetrain vibrations and make the car smoother. Making the guibo stronger makes it absorb less, so then it doesn't do what it is supposed to do. Making it absorb more makes it weaker.

That's why I'm so suprised the M division uses them.

**PbFut** · 06-08-2007, 05:40 PM

Important tip

When you are torquing down the bolts, be sure you turn the nut or bolt that is touching the metal flange. Hold the nut or bolt touching the guido stationary. You do not want to torque load the sleeve in the guibo or you will get a premature failure.

**fmcfad01** · 06-09-2007, 05:18 PM

Can someone let me know if I need to buy and replace the 'Centering Sleeve', nuts and bolts when replacing the guibo? I'm not sure if the nylon nuts are reusable...

**SunzOut** · 06-09-2007, 06:56 PM

Get new nuts..if the bolts look bad (rusted) replace them as well. I reused the centering sleeve as the car only had 30k miles. Just re-geased it.

**fmcfad01** · 06-12-2007, 08:36 PM

Ok! Just did the flex disc and tranny fluid. I'll go in order:
1. Flex disc: the reason i replaced this is because its cracking. When in low rpm's in first gear while rolling at a very slow speed, if I hit the gas, my car would rock back and then move. Likewise, when in first gear at high RPMs, if I let off the gas, my car would lunge forward and then decelerate.

Verdict: It doesn't do that crap anymore...glad I replaced flex disc.

2. Tranny Fluid: I went with Redline D4-ATF or whatever that one is that everyone suggests. I opened up the two plugs and some really freaking gross blackish brown stuff came out. I say some because it was way way less than I would have expected. I'm not even sure a quart came out. I filled it back up with 1.5 quarts, maybe a little more, until the fluid came out of the fill hole. I definitely put more in than came out...I'm questioning how that fluid is supposed to be lifetime.

Verdict: Much smoother shifting. If you are one of the people thinking you can just go along with never changing this, think again. Mine definitely needed to be changed and seemed very very low.

Overall, big improvement.

Scott

**2kredz3** · 06-12-2007, 10:39 PM

kwel, i need to do the flex disk asap. . .how much did that alone run you?

**fmcfad01** · 06-12-2007, 10:43 PM

Originally Posted by 2kredz3

kwel, i need to do the flex disk asap. . .how much did that alone run you?

Got it for $80 and change at BMW of the Main Line. That was $9+ off for the BMWCCA/internet pricing. You need to get the nuts as well.

**2kredz3** · 06-12-2007, 10:46 PM

aight, just found mine. . .i think it is smaller then yours.

showing products for 2000 Z3 2.3.

(Click for a larger image) Please note: Standard Transmission
Part Number Description Price Qty. 26 11 1 227 410 Flex Disc Guibo
$44.95

+ the bolts and nuts. . .hmm might need to order it up!