CV Joints

Technical and Repair Discussions

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PostPosted: Fri Apr 25, 2014 9:33 pm
Ah but Greg, you neglected the whole scientific mouse fart comparison :lol:
It's better to be last on the grid at a race track, than have pole position at the Funeral Home.

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PostPosted: Fri Apr 25, 2014 10:43 pm
Lee Spuhler wrote:The Ideal gas law is derived from Bolye's law and Charles' law is PV=nRT where n is the number of moles of gas and T is in degrees Kelvin or K. 0 degrees C is 273 degrees K, so air tempature is about 300 degrees K. R has something to do with molar mass and avogrado's number and is a constant in this case anyway, My memory tells me it is around 8 but I wouldn't bet on that. (after all I was wrong once today already, I got out of bed and my feet hit the floor, to which I heard my wife mumble "damn it")

First off the number of moles of the gas in the boot is very small and as stated R is a constant. Assuming the operating tempature rises 50 degrees then there is about a 20% change in tempature. I think it is safe to say that the small mole number of the air in the boot is going to dominate the calculation. So a 20% change times very very small leads me to estimate that the pressue volume change in the boot is about the equvaliant of a mouse fart!

There are terms in the post that i have not heard in..uhh...30 years+ Avocados number? Can anyone say sophomore chemistry?
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PostPosted: Sat Apr 26, 2014 9:55 am
srf99 wrote:Well... I pull everything apart every winter, which means taking the CVs off the half shafts. I then clean out the old grease, repack thoroughly with new, and then put everything back together. I haven't yet found a way to reuse the clamps, and even if I did, I'm not sure I'd want to. .

Yes...Perfect
Lotus5 wrote:To repack with grease, you are just pulling back the boot adding grease and replacing. Not removing the axle. Correct? What do you do about the metal boot clamps. Replace them each time?

Also yes. Just pop the boot off and check.
Add greese if necessary by using a gun and push it all the way back to the tri-lobes with your fingers.
No tools required.
Then push boot back on.
CV boot band should be snug but, not so tight that you can't pop the boot off.
Small CV band on the tri-lobe is tight.

Small CV band on the outer (short side) is loose or use a straw.
Large CV band on outer (ball bearing CV) is tight.
(I use the blue silicone outer boot on the left side and that one can take the heat)
GregCirillo wrote:I'm no engineer, but have my doubts about the "excess pressure" issue. Really, how hot can it get? Starting pressure is 0 lbs at ambient temperature. Even if it heats up to 175 degrees, what sort of PSI will that create? And why can't a very flexible boot handle that increase in pressure?

Next time, after a race, jump out of the car and check your short side boots.
They will be bulging (inflated) if you have them tight.
I don't know what the temp is but it is hotter than the valve cover.
I'll check with an IR gun next time. :D

The 2 weakest links in the SRF are wheel bearings and the short CV shaft assembly.
(left rear wheel bearing is worst then right rear, left front and right front)
Low camber and ride height aggravate the short side CV problem.

My method makes a mess, but I have never had a mechanical DNF.
I have had an electrical DNF twice for the same thing :evil: but that is another story.
Dave Gills
#80 Red/Silver (chassis 504)
Pittsburgh, Pa.

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PostPosted: Sat Apr 26, 2014 1:16 pm
Dave

I don't know how other people feel but personally I have a real issue with setting up a car KNOWING that you a leaking oil or greese onto the track. I am no expert on the GCR but it maybe counter to some rule someplace. At the very least I think it irresponsible.
It's better to be last on the grid at a race track, than have pole position at the Funeral Home.
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PostPosted: Sat Apr 26, 2014 3:37 pm
I don't know as I've ever see my CV boots bulging after a session. Then again, I don't use the grease that comes with the CV kits, as it turns completely liquid when it gets hot, and I'm not sure how well that lubes and protects the CV. When I repack my CVs at the end of every season, the grease looks nearly new...
Dan

Formerly Teamwork Motorsports #99, Chassis #460
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PostPosted: Sat Apr 26, 2014 4:35 pm
srf99 wrote:I don't know as I've ever see my CV boots bulging after a session. Then again, I don't use the grease that comes with the CV kits, as it turns completely liquid when it gets hot, and I'm not sure how well that lubes and protects the CV. When I repack my CVs at the end of every season, the grease looks nearly new...


I'm with you, Dan. It's no fun to open one up and have some liquid drip out and find big blob of crap in the boot. :)

What kind of grease are you using? We have done o.k. with the blue grease, but it seems like Redline may be a little more durable.

Dave
Dave Harriman
"It looks crazy, I understand. But, we only live once and I am going to give it a good try." - Alex Zanardi
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PostPosted: Sun Apr 27, 2014 9:44 am
I've been using Mobil 1 Red for many years, and following the once-a-year maintenance I described earlier, it's barely turned a burgundy color when I clean it out the next winter. Although I'm not gonna say anything that might tempt Murphy to show up... :-)
Dan

Formerly Teamwork Motorsports #99, Chassis #460
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PostPosted: Mon Apr 28, 2014 1:17 am
This may be my last post here :D
Dave Gills
#80 Red/Silver (chassis 504)
Pittsburgh, Pa.
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PostPosted: Sat Feb 07, 2015 12:25 am
Which grease is best for CV joints? I've been using Mobil 1 synthetic for everything on the car (CV joints, wheel bearings, rockers, ball joints) but I just saw on this forum http://www.bobistheoilguy.com/forums/ub ... /1861460/1 that many people don't like it. I guess I have 2 questions... What's the best grease to use for CV joints? and is it ok to use that same grease on all the other grease applications in the car?

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PostPosted: Wed Sep 25, 2019 7:00 pm
have a question both ends of the half shafts show blueing from heat. the inner race on the wheel end is showing blue where the ball bearings run and on the outer casing, also on the tripod end. Or do i just look for bad wear. This is my first rebuild of the half shafts. Just wanting to know what is normal.
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