I dont know how well armor all protects rubber, although thats what they sell it as. I do know the 303 stuff works great. I used it on my boat seats that sit out in the sun for 8 months every year and they are perfect after 5 years. Without it, they would be alot rougher. I use 303 on the drive axles of all cars I service. I work mostly on VW TDI's, and the 96-97 passats inboard CV boot on the passengers shaft is extremely close to the turbo and is always the first to go, sometimes before 100,000 miles. It was such a problem that in 1999 VW added a heat shield in that location. Ive been spraying my neighbors passat every oil change or service and they look brand new. No scuffing from turning, no dryrot cracks, nothing.

I have also used it on the CV joints on my 300D, they have extremely deep cracks however they dont seem to be getting any worse and as far as I know its the original shafts with 240,000+ miles. Turbodiesel owned it prior to me, he might know if they were replaced, but still going strong!

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Matt
2003 Jetta Wagon TDI 145,000MI
1999.5 Jetta TDI 287,000MI
2001 Suzuki SV650S 26,000MI
2008 Yamaha Vino 125 11,000MI
http://www.crazymatt.org