Toothed belt tensioner won't budge '04 A8 4.2

[terbogoat]

The Bentley instructs me to turn it counter clockwise with steady pressure until the locking pin can be inserted. I'm twisting pretty hard and getting no movement whatsoever. Am I missing something or have I lost my muscle tone?

Mike

 

[jyoung8607]

The key element is time. The hydraulic element is slow to adjust by design and you don't want to force it. Apply steady pressure over the course of two or three minutes and it will slowly compress. You don't need a crazy amount of force. Once it's down far enough, insert a pin, or a small drill bit if you don't have a spare. Don't steal the pin from your new one; you don't want it to expand until it's installed.

Do the reverse when installing a new tensioner. Don't just "pull the pin". Apply a bit of pressure to allow the pin to be removed, and then slowly allow it to expand over the course of a few minutes. Failure to do this can dramatically reduce the tensioner service life. Ask me how I know.

Jason

 

[terbogoat]

Hi Jason,

I knew it takes time but I was counting in seconds, not minutes!

Thanks for the advice, I'll give it another go.

Mike

 

[Gavra]

Heat it up to 70*C , tensioner MUST be in vertical position and you should apply around 150Nm force to it and wait for about 1 mm retraction per minute. Or pay 550$ for new already locked

 

[Jack@European_Parts]

It should compress in 5-10 seconds and it is with resistance.

Never apply heat to the tensioner, it is charged with gas!

If you want, take it out and send it to me and I will compress it and install the grenade pin for you.

 

[jyoung8607]

Heat it up to 70*C , tensioner MUST be in vertical position

I've heard of a need to keep it vertical, which isn't a problem when compressing it while installed. But heating it is news to me. Can you cite a repair manual or parts manufacturer instruction for that?

Anyway, assuming the OP is planning to replace the tensioner, he's free to do whatever it takes to remove the old one. After all, it's trash. But if you ever end up having to R&R one you intend to keep, treat it very gently.

Jason

 

[jyoung8607]

Show us a picture of where you are applying PSI with a tool please

The OP should be using a hex socket with a ratchet or breaker bar, inserted into the hex fitting in the eccentric tensioner roller/pulley, applying moderate clockwise pressure to slowly retract (or slowly release) the hydraulic tensioner piston via the tensioner arm. When installing a new one, observe the instructions in your repair manual carefully, you'll actually let it come out all the way (slowly!) and then actually help it along a little further counter-clockwise to a particular torque spec, pre-tensioning the belt along its entire length before you torque the cam sprockets down onto the cams.

I have given Blauparts enough money that I trust they'll forgive my borrowing their image...

Jason

PS: slloooooowwwly. I mean, unless you like seeing purple hydraulic fluid and bent valves.

 

[Gavra]

I always heat them in the WATER, and they are hydraulic there is NONE ever existed filled with gas.

Part number for this car should be 077 109 479 D and on any car, automatic tensioners are ALWAYS filled ONLY with fluid in LIQUID state because fluid in GAS state is EASY to COMPRESS and can NOT be used to apply steady pressure to timing belt.... and if you go to Dayco website you can see warning about storing tensioners because if air leak happen to one due to wrong handling you need to pump it several times from compressedto fully extended position in order to save warranty.

Jack please do not take this personally, but this is elementary of physics and we are learning this in fifth grade here

 

[terbogoat]

Got 'er done!

Firm steady pressure (about a minute) is what was needed. I noted little to no movement on my handle but eventually noticed that the belt was becoming slack. The tensioner was replaced along with the belt kit and coolant pump just before we acquired the car so I do not intend to remove it from the engine. I merely needed to slacken the belt in order to get the cam sprockets back to correct alignment. Evidently the repair facility assembled it without benefit of any locking/alignment tools.

Thanks again for the tips. The Bentley is a good guide but assumes knowledge of certain details... knowledge that this guy does not possess in abundance!

http://imgur.com/2ScgzJ2

Mike

 

[Gavra]

Well if you wanted just to correct timing you could do it without slackening belt...it is build in that way that you first tension belt then you tighten camshaft sprockets......

 

[ivagp]

now put your vag com on and check all the good stuff like cam phaser 90 somethig.

 

[ivagp]

now put your vag com on and check all the good stuff like cam phaser 90 somethig.

 

[terbogoat]

Well if you wanted just to correct timing you could do it without slackening belt...it is build in that way that you first tension belt then you tighten camshaft sprockets......

Ahhh... but the silver lining is that I now know exactly how to do it without the need to come here and whine for help!