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850 distributor rotor -- removing a stripped 3mm internal hex bolt

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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jreed
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850 distributor rotor -- removing a stripped 3mm internal hex bolt

Post by jreed »

I replaced the rotor and cap today on my '97 855 GLT. For some reason years ago when I originally installed it, I over tightened the small 3mm internal hex bolts that hold the rotor to the camshaft. While loosening one of them today I stripped it. The stripped bolt is at the lower right, at about 4 o'clock.
IMG_9477.JPG
To remove it, I used a tiny pair of self-locking pliers to grab the outside of the head.
IMG_9481.JPG
The little pair of pliers had just enough grip and gave just enough leverage for me to break loose the bolt. Once it was broken loose a bit, I was able to back it all the way out with a 3mm bit.
IMG_9482.JPG
So, I was happy I got my self out of a situation, and I thought I'd just write it up and share in case any body else gets into a similar situation, or just as a heads-up not to over tighten the bolts when installing the rotor. The bolts have a locking ring and don't need to be tightened extremely tightly in order to hold the rotor securely.

Once I got the rotor out, I noticed that the old one was slightly different: the brass plate at the top was not as flat and not recessed as deeply as the new one. Also, the chamfer on the internal hex was a little larger on the old rotor compared to the new one.

In the pictures below, the old rotor is on the left and the new rotor is on the right:
IMG_9486.JPG
IMG_9488.JPG
I think the new rotor looks a little better made. Both are Bosch. The new one was in a box marked "Made in Spain". I installed the old rotor about 7 years ago and I don't recall where it was made.
1997 855 GLT (Light Pressure Turbo) still going strong. Previous: 1986 240 GL rusted out in '06, 1985 Saab 900T rusted out in '95, 1975 Saab 99 rusted out in '95, 1973 Saab 99 rusted out in '94
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abscate
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Re: 850 distributor rotor -- removing a stripped 3mm internal hex bolt

Post by abscate »

I only have distributor-less Volvo’s but my guess is the contact I the cap is spring loaded so it will pick up that contact fine.
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abscate
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Re: 850 distributor rotor -- removing a stripped 3mm internal hex bolt

Post by abscate »

Not sure what the torque spec is on these 3 mm Allen head or hex head bolts but for those playing at home I used a hex driver and finger twist torque only, quite light.

Visually, I would just flatten the lock washer on the bolts onto the plate

Don’t have lockwashers? What have we told you here about using cheap parts?
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary
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