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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
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1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
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850 distributor rotor -- removing a stripped 3mm internal hex bolt

Post by jreed » Sun Apr 05, 2020 4:13 pm

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.
To remove it, I used a tiny pair of self-locking pliers to grab the outside of the head.
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.
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:
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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Re: 850 distributor rotor -- removing a stripped 3mm internal hex bolt

Post by abscate » Sun Apr 05, 2020 6:42 pm

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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