How to Replace a Flex Disc

In this episode of Saturday Mechanic, Ben and Russ shows how to replace a flex disc on a viewer's Mercedes-Benz.
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In this episode, Popular Mechanics' Associate Auto Editor Ben Wojdyla:
* Disassemble the flex disc
* Reassemble the flex disc
Who says you can't work on your own car anymore? Follow Popular Mechanics associate auto editor Ben Wojdyla as he leads viewers, step by step, through repairs, upgrades, and troubleshooting tips. Got car questions? Email Ben, and he may answer them on the show.
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[@Jacob.Morningstar]

This helped me out immensely, I will be doing this exact repair in my C36 soon. It's not my daily driver so I dont have to worry about it failing on me. Thank you, this video is awesome!

[@godzillasballs]

this vid is better the many of the previous ones - slowly, you are getting better

[@acetech9237]

Never tighten down nuts and bolts on a driveshaft in a circular motion. Those 6 bolts should be tightened like a wheel. Equally spaced in a triangular pattern.

[@Terraceview]

I love these vids, entertaining, educational and meditative. Keep this up guys.

[@MonteOlsen]

Great video. Really appreciate the care you took to make it, particularly the different angles and good lighting.

[@fredbrooks9439]

Thanks guys I will be doing this repair very soon to my Chrysler 300 2008 and you guys make it look so easy and smooth to do I'm excited to get started 🙂❤️👍🏾👍🏾👍🏾💯💯💯

[@jasoneyes01]

Drive shaft center bushing is worn, that is the little bushing in the driveshaft. That is a vibration maker as well...

[@StuartOliver83]

Thanks Mate I’m doing this at the weekend,not sure I have one at the diff,only at the gearbox end but I may be wrong,one question please,will I need to drop the centre to allow me to pry the shaft back? Thanks in advance 👍

[@prasobhgdas7578]

Hello thanks for your information. Also my w124 had the same problem and while im inspecting the differential i had seen there is some one rubber parts which hold the differential on the frame was damaged. I need to replace it and how it will do

[@tomchristensen2914]

You forgot to mention that some guibos or flex discs are directional... and if put in backwards will perform bad and destroy itself...

[@ashingtongwexa4373]

Maybe that’s why mine makes vibrating sound the one by the transmission

[@waynerobati6940]

Nice detailed videos! Thankyou!

[@erictold]

The fiber reenforced flex discs usually last more than 150,000 miles. Video is well made. Thanks.

[@Peter-td3yk]

But the carrier bearing sure wont>>>>

[@JaisenJames]

Thanks for the tip! I'll check it out.

[@thereglis]

nice job. keep em coming.

[@johanwelthagen1059]

Hey there, I have C200 Kompressor, would this be able to cause a clicking sound coming from the center dash. increases with speed and changes volume dependent on what side you are turning to?

[@mcycleserv]

great vid ...have a question in regards to dive line ...e46 232i 2002 ..190000km auto .. car is smooth without any vibration but!! at 120kph there is not a vibration but a hummmm from seems to be from centre to rear of car ...any suggestions

[@marcosvazquez9380]

I have a 05 Cadillac cts 3.6l I was wondering if I can follow this same procedure for checking mine?

[@luismadafaka8648]

Hello, very nice video Please make more to learn more in depth of how to fix this type of things! it would be amazing to have a vid with several common noises that a car could have..! and what they represent! for this vid, could you feel the difference in the driving after changing this piece? Thank youu! respect

[@JEL2011able]

Great job guys! Perfect presentation to help us diy guys and gals.

[@Elchullaquiteno1]

hello I have a question on a s430 the valve block for the air suspension what's the procedure in the install ???

[@yugo63]

Excellent Thank-you,

[@mattgrim2385]

you were great !tks a lot

[@danieltahin4164]

Dear Ben. Thanx for the good explanation. I have a Mercedes c240 (2003). Do you know after how many miles the flex disc should be replaced (or inspected)?

[@078dude3]

Daniel Tahin you should inspect it after 10 years or around 100000km

[@Highlander339]

Great video. I have a 2002 BMW 330i w/ 83k mi. When I step in the accelerator at around 70mph, I can hear a slight rumbling noise coming from the middle/rear of the car. When I take my foot off the gas, the noise seems to disappear. What problem(s) do you think it is? Thank you.

[@rxpx69]

Hungry dinosaur in your fuel tank

[@skiraf]

Do you have a video showing the steering coupler (rag joint) which is similar to the fex disc?

[@thelongranger55]

Good suggestion .

[@facesofpigs9927]

can u post a picture of how the original driveshaft coupler that connects to the transmission looks?

[@Elchullaquiteno1]

is there a certain direction the flex disc goes or can it be either way ??

[@tazzmenn]

Chulla Quiteno the label or writing on the rear faces forward on the forward flex disc the labels faces back.

[@dogpwr]

What size allen wrench was that for the new hardware?

[@dwilliams2068]

There are several comments here about replacing the flex disk with something solid. Only issue is that these disks have to do the job of a universal joint, so a solid disk would destroy the whole drive line. Please someone repeat the torque specifications and I agree with turning the nut instead of the bolt.

[@Lincolnls00arturo]

I was doing this to my cayenne but I dint mark the drive line. The drive shaft separated on 2. I put everything back together and it looks good. Now i got the drive shaft out of balance. How can i balance the drive shaft with out tacking it to the shop?

[@williewill8733]

I have a 2003 S500 when I accelerate I get a weird noise would that be my problem?

[@melvinriddick7325]

Will the flex plate cause the transmission to drop down and then when I put it in gear it does not move

[@CaptainEOOW]

What is the torque value (2005 SL 500)? Great video, thanks!

[@goldm81]

what are the torque specs in Nm? great video!

[@michaelb8957]

60 Nm

[@redeemernigoohaem9735]

Hy, same for me, I have a w202 c180, I can t find the transmission mount . Is it cuz it s manual ?

[@antonycurry1263]

Hello, is it the same tutorial with Golf 7 R flector?

[@julianpina3771]

Was it making a rattle? Or noise when idling in park or drive?

[@ReligiousShooter]

The phrase is "Like a BOSS."

[@daimasongoodspeed]

now I know what a flex disc is!

[@mannycweiss3053]

Mercedes uses some of the strongest Donuts in the world. I had an Alfa V6 with probably 175hp, granted it was a transaxle car but that car went through donuts like crazy. The alfa donuts though, came with a strap around the outside of the donut making the holes closer together, once you have your bolts in, you clip the clamp off and it expands and you're done, i guess benz doesn't pre-load theirs

[@scabberdoug]

Good video. One suggestion to better remove the old disc would be to use a 10mm pin punch or allen wrench and insert it into the metal sleeve then pry it instead of prying on the rubber. Much safer and easier.

[@Incountry]

That’s not an Air Ratchet, that’s an Angle Air Impact Ratchet ..!! Big difference.!!

[@tonyt8796]

If working on a '97 Mercedes C230 or similar, remove the rear exhaust and heat shield, then loosen the center bearing to gain clearance to remove and replace the disk, there is no way to force the driveshaft back to clear the pin in the center of the differential mount. Unless you are working from a lift, the length of the bar you can use to force the driveshaft back is limited, and there is no room for a helper. After loosening the bearing mount, the driveshaft easily slides back enough to align the shaft to the differential.

[@Peter-td3yk]

YES, carrier bearing needs replacement too.. and boot.. But loosen driveshaft nut colapse drive shaft.. or damage the centering bearing grease filled worn out too. Had a driveline balance shaft too.. installed new bearing and mount for free..

[@edwardprice8649]

Can you do a video for the front by the transmission 🤔

[@davidpeete7216]

mercedes benz 420sel 1988 what way flex disc go on do it have front side and back side and my mark got wipe off to line up now i am get a vibration in the rear how do you balance it please help

[@CobraCobra33]

Ist es beim e91 gleiche Arbeitsweise? Oder muss man da noch was lösen

[@clk5005]

Will this also cuase a rattling sound while driving around 30 to 40 but goes away iff i keep my foot on the gas,iff i let off while it slows down i hear metal on metal rattling coming from back side

[@fernandogonzalezruiz6199]

hello I have a mercedes 180c w202 if I accelerate a lot, it will bump a bit when driving, it is no longer gears well, it is the hardy disck thanks greetings fernando Sout spain

[@fredkord3177]

How Can I replace "front drive shaft" for 2004 Mercedes Benz ML350?

[@ta2stop]

Whats the torque for the bolts...?....and nice video very helpful for DIY...

[@michaelb8957]

60 Nm

[@maxamillian3487]

found the isse brok on the on ramp my front drive shaft had worn u joints 300 on ebay with replaceable u joints versus same part at mb usa for over 1000 pus shipping from germany and then to my house

[@SuperDavaughn]

how long does the flex disc normally last on the car??

[@bilzt4083]

Hi what was the position before and after replacement. Dear I could not see.

[@sojivarghese2566]

Is it similar for a 2007 W221?

[@peterpetersen231]

Hpw does one remove gear selector cognition cable on a mercedes c280 1999 model automatic box please on left side of gearbox

[@matthewplacencia609]

OEM? or aftermarket parts?

[@BoNuSSoftware]

Any specific tork strength ? Nm ?

[@johnmanns9413]

Why not change the the rear one at the same time in this case? I am glad that you highlighted the fact that you needed new bolts!!! I didn't know that when I was a kid and failed to replace a torque to yield bolt - had to get a tow home :-O

[@changeyourenergy708]

That is the back one. I was wondering why the front one wasn't addressed

[@fatboy5599]

Is the front flex disc the same as the rear flex disc?

[@CharlesOwoyemiAdeniken-cd3pj]

Slow acceleration of my W201 190E 2.0L. Front wheels vibrate when braking. What could be responsible?Can my leaking water pump be repaired aside replacing it with a new one? Please help. Thank you.

[@TimothyJHoney]

How would you do this on a 2003 T4 Syncro?

[@ryanmyers179]

Do you have any idea, what could be the problem if you have to replace the flex disc 2 times in 3 years? I have a 1992 Merc. Are the parts old or do I need original parts?

[@adriangutierrez8177]

Ryan Myers My guess would be improper installation. Along with the flex disc, the center support should also be changed. If one is failing it will cause an in balance and do harm to the other component.

[@skiraf]

make sure you support the drive shaft before you remove the bolts.

[@broken55muffler31]

Would that piece also make car vibrate at higher RPM's??? I

[@seetkukkanen767]

I have that issue now in my e91.

[@atos.nympha3451]

that was easy ..was wondering how much it will cost to do same thing at the dealers and how many hrs they say it took them to fix this ugh.. thank so much for this video

[@hNig3Lh]

is this for W210 E300 DIESEL.. THE TRANSMISSION IS 5SP AT

[@oneminutefixed5003]

do the bolts need a specific value to be tightened ? I can't recall the name of the tool that does that, dyno something i think

[@seanellen6514]

a torque wrench

[@rasirie6299]

OneMinuteFixed yes. Direct screw is 120 n.m and like the one in the video is 58 n.m

[@GraylingLooney]

Are there washers on each bolt

[@rurouni.benjaminkenshin2637]

Do u have to use new bolts or u can use the old ones

[@lionofjudah4574]

You NEVER use the old bolts and nuts from the old flex disc. Most are sold with a new set of them.

[@johnpullen4750]

Dealer gave me a quote for $600 to do this on my '06 E55. Bought the part for $150... it's up on my lift and I'm gonna give this a shot!

[@johnpullen4750]

Crap...the drive shaft on my W211 has a center shaft that is making this a total bitch to do.

[@KelvinSmoke]

are the bolts blue because of pre applied locktite?

[@doe8939]

Would this cause a "clunk" when shifting into reverse?

[@farerse]

yes among other issues. but start with new giubos and centre bearring support

[@Motorsportsgeek]

I replaced my front and rear flex disk on my mercedes c300 but I failed to mark the position of the driveshaft and now I have a slight vibration at 70mph... What are my options ?

[@palewriter1856]

Since there are only 3 possible match-ups, and you're not liking the current one, trial-and-error isn't all that difficult: you've a 50-50 chance that the first (of the remaining 2 options) other position you try will be the correct one. If not, well - look at it this way: you'll be getting pretty good at the procedure. Plus - you only have to R&R 3 bolts for each new try. Here's a hint, though: this time MARK things so that if your 1st guess doesn't get it, at least you'll KNOW which is the 3rd (untried and presummably correct) option remains!

[@frederickralston1842]

That pilot bearing in the end of the driveshaft would have liked some lubrication.

[@TyphoonVstrom]

It's not a bearing, it doesn't need lube.

[@Robert.K]

It's a centering sleeve and it is supposed to be greased.

[@brainwashed7244]

if the centering sleeve is damaged can it be repaired? or do i need new shaft

[@JaisenJames]

Do all 4wd or RWD setups have a flex disc? If not can one be added? My truck has a similar problem when power is applied.

[@nihonkokusai]

Only BMW and MB has his flex disc a.f.a.i.k.

[@kristyl3418]

is it possible to tear the front flex disc when replacing this one?

[@user-nh6vk5uh4t]

Kristy L no

[@barryjanis]

In order to transport my Mercedes C-280, seventy five miles on a car dolly, I need to remove the drive shaft, and now I know how, Thanks .

[@maxamillian3487]

i have a clink on my car when shifting into reverse any clues on what it might be

[@seanellen6514]

if its manual, a clink while shifting gears is usually normal. if its automatic there could be something lose in the linkage from the shifter and the tranny, or there could be something lose in the tranny.

[@gregorymalchuk272]

Canadian Guy What is a "guibo"? A gearbox?

[@RideandDine61n61]

@peter d Is this the same as the tranny mount?

[@ricardolpd]

No its an e-class (99-2002 or 2003) she had it in the show before to replace a front suspension spring.

[@galepatterson670]

What way was the arrow pointed on the gibbons the front or back of the car

[@mushedroom]

so i know they didn't really address this in the video but... would a bad flex disk cause heavy vibrations only around 40-55 mph?

[@user-nh6vk5uh4t]

mushedroom's toy box unbalanced wheels will. And yes but not to common, unless it's already grenaded

[@ADG0086]

hello you know how change the flex disc on mercedes 190-d w201 ?

[@tazzmenn]

FÁBIO CARVALHO it is the same for w201

[@michaelb8957]

Buy quality brand discs like MEYLE or they won't last, also lubricate the inner bushing with hi temp grease or replace it if necessary then tighten all bolts in a star pattern like you would your car wheel to 60 Nm. Make sure you assemble the disc correctly and the washers go on the bushing holes not the drive shaft.

[@Slysdexia2]

As I understand it, flex disks or guibos as some call them, are a European solution. More common on rear wheel drive US vehicles and most heavy duty trucks is a universal joint, or cardan joint. In your case, it could be a worn universal joint or a transmission mount. I had a truck with a similar issue, replacement of the transmission mount, which is inexpensive and fairly simple to install, fixed the issue. A worn transmission mount or U-joint would be easy for most shops to find and fix.

[@unicornbbq]

Ben! Ben... oh my gawd, ben... It MIGHT help to tell folks if you have a lift, great, but if you're doing in the driveway, you can't rotate the shaft unless you lift one of the rear wheels. With it lift it would have taken me 20 minutes tops. On my back, in a muddy rain soaked driveway, 4 hours since we were not able to move the axle.Also, might mention that there are TWO of these things on the car, right? And you're working on the rear? I'm not a mechanic but considering nobody noticed that the flex disc was failing at ANY of the 6 oil changes I had in the last two years, or the jeckhole who we got to solve the vibration in the stick shift. Turned out the flex disc was breaking apart and slapping the shifter rod and ended up wearing out the coupler from the shifter to the shift rod. He was under the car twice to repair it, once, quick-fixing it so we could drive it, and second to install the actual part. NEITHER time did he notice the flex disc was showing threads and broken up. Again, I'm not a mechanic but when I looked under the car to see why even after the proper shift coupler was installed we still had vibration, I saw this mess RIGHT AWAY. Seems like the cause for the failure was 1) only 4 bolts had been used to install the thing. 2) looks like they had been cranked down with too much torque and had warped the washers and the rubber. What i removed from the drive shaft was just a pile of broken rubber chunks, some coupler sleeves, and a lot of exposed threading holding it all together.

[@TyphoonVstrom]

So, lift the vehicle at the rear, so the wheels are free to rotate. Use your brains.

[@ram457moreno]

do you know if a 1989 Mercedes 300 se have two flex disk ?????

[@MiamiViceGTA]

+romeo moreno On the front and on the back.

[@ParthPatel-zy4pg]

I think i need a new flex disc but literally cannot find them any where for sale for my vehicle 05 merc ml500 w163. can anyone help?

[@user-ue4qy2xd4l]

Did you check fcpeuro? I have been able to find almost every single part for my '06 C230 on there, and for great prices as well.

[@edwardandrade4390]

Should you have used thread glue?? Lock tie

[@robert_murphy916]

can this make clunking noise when pushing car back-and-forth

[@maxamillian3487]

i found it worn flex disc and rear cv axle

[@ghettobird2012]

I wish it would've shown how to line it up

[@BizzyVlogs]

LOL definitely the wrong size wire brush

[@lakloplak]

Just to inform you, you spelled DYI at 3:55

[@mancinoxvii]

Flex disc public service announcement: don't wait until it's too late. If the piece fails the driveshaft apparently destroys everything in a circular path, even cutting into the cab! Google "Failure of the Flex Disc on a 126 Body Mercedes"

[@TyphoonVstrom]

No it doesn't, there's a centre locating pin that prevents that.

[@blairgordon4911]

look at him struggling to get that shit off, it helps if you have more upper body strength

[@kevinhancock4064]

When you say centre bushing do you mean centre bearing? I believe mine is going as I get slight vibrations on acceleration I will probably have my flexi done too at same time only thing I'm unsure of is when I had my flywheel and clutch done on my BMW e46 the mechanic didn't put marks on there when removing the prop shaft??? To align correctly when putting back together as I was there with him doing it

[@raphaelandrew6631]

I own a Mercedes Benz clk55 amg. My center support drive shaft bearing and braket was busted(drive shaft was very loose in center). I DIY it, I replaced the foward and aft flex discs and also the center support bearing and transmission mount, I forgot to MARK everything before I took it apart. Put it all back together NOW the car vibrates at around 50 mph. Can't find a shop in Orlando Fl. That will rebalance the drive shaft. Should did more research before started. 😔

[@rueliotube]

Raphael Crandon I don’t know for sure about the clk55 but after 1985, Mercedes pretty much started casting marks into the driveshaft halves so you can just line then up when putting it back together. No need to make marks yourself.

[@sportsmansparadice42]

Is that a W124 mercedes benz?

[@maxamillian3487]

would the flex disc make a clink when shifting into reverse if worn

[@Razor8661]

Yes I just replaced the front flex disc on my c230 and I would clunk when downshifting from 2nd to 1st and when moving into reverse. The problem was the bushings in the flex disc were loose

[@maxamillian3487]

Thank you

[@Razor8661]

also just to let you know there are 2 flex discs one of the front of the driveshaft by the transmission and one on the rear like in the video the front one is subject to way more heat

[@elkillerx]

Titus Nickleson True. I just replaced the front flex disc on my w211, It was not clunking when shifting but the car had a slight vibration at highway speeds. Problem went away after I replaced it. Surprisingly the rear flex disc looked good with no cracks whatsoever so I left that one alone.

[@christophebaudel1776]

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