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First 6hr Service on SR10 - Lessons Learned

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Clark Darrah
(@clark-darrah)
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Thought I would post my experience having completed the 6 hour service on my SR10.  By way of background I'm fairly competent doing basic service stuff on my other cars (engine, trans, diff oil changes, brake work, suspension, etc.) but when it comes to the more skilled things like pulling and rebuilding a gear box I'll leave that to people more experienced than myself for now.

Overall, the process was pretty straight forward but the Radical instructions were directional at best.

Brake Fluid & Pads

I use a Motive bleeder and got the Tilton adapter which makes the process fairly easy with the exception of having to maintain about 15psi in the bleeder.  Changing the front brake pads is straight forward by just removing the calipers, push the pistons in and putting in the new pads.  The replacement pads I used were the PFC 7745.01.16.44.  The rears didn't need to be changed but look like a real pain because of the carbon fiber shroud that covers the rear disk.  The caliper bolts look like they're easy enough to access but they're not.

Gearbox Oil Change

The manual shows the fill plug easily accessible before the car is fully assembled.  The problem is that once it's assembled there's a bracket that goes over the top of the fill plug that covers just enough of it so that you can't get a 1" socket on it.  I had to unbolt the rear body panel, slide it up and grind a little of the bracket back to get the socket on it.

IMG 6095

The manual also shows the drain plug being safety wired to the gearbox.  It is not - it's safety wired to a bolt at the back of the gearbox.

IMG 6076

 There also aren't any torque specs for for the plugs so I just snugged them up and put the safety wire back on the drain plug.

Oil Change

There seemed to be a variety of opinions about which lines to unhook and plugs to open.  I ended up just following the manual and removing the AN line at the sump that goes to the oil container.  I had to use a 30mm thin wrench and #12 AN wrench to disconnect the line from the fitting in the sump.  I got about 5 liters of oil out and then also disconnected and removed the sensor in the bottom of the oil container but no oil came out.  Re-connecting the AN line at the sump was a little bit of a pain because the frame doesn't really allow you to get an easy angle to start threading the line back on to the fitting.  It may have been a lot easier on a lift.

The manual calls for 6.75L of oil.  I put in 5.5L and it was overfilled so I sucked out about 0.5L.  This leads me to believe there are other plugs or lines that need to be disconnected to get all of the oil out of the engine.  In hindsight I should have just disconnected the other AN line going from the sump to the heat exchanger to see how much would have come out.

The oil filter that was on the car was a Mahle OC 384.  The oil filter I used was a Napa Gold 7035 which was recommended by my Radical dealer.

Drive Shaft Grease

This was by far, the biggest pain in the ass because of the mess I was able to make with the grease.  Removing the drive shafts was straight forward - remove the safety wire and top bolt (the manual shows it as 7/16" but it's 5/8") on the upright and H8 bolt connecting the wheel hub to the drive shaft and you can tilt the upright outwards, remove the drive shaft from the wheel hub and then pull it out of the housing that stays connected to the gearbox.

You cannot find the Radical recommended grease (Total Lithium EP2 400g) so I used Lucas Oil Red N Tacky which is what my Radical dealer uses.  The manual says to use 100g per joint which seems to be WAY too much!  When refitting the boots, grease was already squeezing out so I probably ended up with about 80g which still seems like a lot.

The correct band clamp for the boot is a 7mm Adjustable Ear Oetiker 163, 98.0mm.  I had originally ordered the 7mm Band Stepless Ear Oetiker 167, 89.0mm based on previous SR3 threads thinking it was going to be the same, but it's not.  If anyone needs some clamps let me know and they're yours.

When I fit the drive shafts back on, I needed to use a floor jack to get the upright to properly align with the bolt from the wish bone.  There are no torque specs for the H8 bolt so I still need to research what it is.

Final Check

I warmed the car up and then went through the gearbox warmup procedure outlined in the manual.  No oil leaks but I did have some more grease getting squeezed out of the CV boots which will only get worse once I get the wheels on and the car gets up to speed so I'll need to keep an eye on it when I get to the track.  

At the end of the month, I'll be doing three days at the track and will have my dealer do the service on the car.  I'll watch them go through it to see what I missed or could have done differently and if there is anything insightful I'll post an update here.

 
 

 

 


   
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DavidF
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Posted by: @clark-darrah

You cannot find the Radical recommended grease (Total Lithium EP2 400g) so I used Lucas Oil Red N Tacky which is what my Radical dealer uses. 

The correct grease is GKN Tripod grease (not CV joint grease and not Red N Tacky).  The method I use to grease the tripod joint needle bearings is with a grease gun and a 34mm tripod greasing tool available in the USA only by special order from Comprent Motorsports.  Ask for Kevin (706) 543-1797 ext. 1.  Taylor Race Engineering no longer supplies these, and only one size is available at Pegasus -- the wrong size.

The GKN Tripod grease is expensive, yes, (you get what you pay for) however with the greasing tool you do not have to fill the tripod housing with new grease every six hours.  Just wipe clean the tripod joints and then replace the grease with the greasing tool. 


   
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Bill Snead
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Great info,  thank you for posting Clark!

I will be doing my drive shafts on my RXC V8 with the Quaife, good to know regarding the specific grease David and the necessary tool.

Hopefully mine is similar.


   
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John Parsons
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I'll defend Radical for once: the upper BJ bolt is 7/16" in diameter, and the bolt head is 5/8" across the flats. 🙂

On the grease, I use Red Line CV-2 (it isn't sticky at all). I don't have any problem getting 106g into each joint, but I do have to spend an hour per joint getting the old grease out of the cups, tripod rollers, and especially the folds in the boot. After I clean all the parts, I use my AC refrigerant scale and put out a mound of 106g of grease. I put on a new pair of nitrile gloves and use the palm of my hand to force new grease through all of the rollers from the outside in. Then glob on more grease to make a big greasy tripod end, and put the remainder in the cup. Slide the boot up and out of the way, put the joint together, then slide the boot over. New Oetiker camps finish the job.


   
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Rod Bender
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@davidf ... Thanks David.  This is a bit of a blind-spot for me.  I never imagined that these drive shafts CV's (SR3) would need such regular servicing.  I've got a 550hp VW Golf R hillclimb car that does 0-100km/hr in under 3.2 seconds and has done over 300 'launches' at 5,200rpm... and all I have ever been told to do is to re-torque the drive shaft coupling bolts every 20 launches.... and never any issues.

It seems strange that a set of drive shafts handling much less power and pushing less weight (and a lot less shock load given the VW is over 1400kg with me in it) need such regular service.

I put brand new Heavy Duty drive shafts in my car when I purchased it (and have kept the old shafts as 'serviceable spares')... I've now done ~15 or 20 hours total engine hours (probably only 10 hours 'on load') so might be getting to a point where I need to do something.

Do you or anyone else know if there is a 'service guide' for the driveshaft joints?  I think I'll service the spare shafts I have and at least get them ready to re-install...

I gather the greasing 'tool' you mention makes it easier, or is it 'required'?


   
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DavidF
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@rjbender 

GKN makes tripod axle joints for many race cars and non race cars, and they sell GKN tripod grease. 

From PegasusAutoRacing.com:

This grease is designed specifically for use in tripod joints. Use of the wrong grease can lead to premature failure.

The needle bearings in tripod joints can overheat easily because the rollers slide along the length of the needles in addition to spinning around them. The very tight tolerances in tripod joints also do not tolerate solid additives, which can jam and cause the bearings to seize. This special grease from GKN has high scuffing resistance, but without the solid additives typically found in CV grease.

 

I believe that my SR3 XX came with GKN Tripod grease because it has the exact same color, consistency, and viscosity. 

 

The owners manual says 10 hours re-grease the tripod joints on SR3.  6  hours for SR10.  I checked mine at 20 hours because for SR3 I think it is overkill to service every 10 hours.  I'm not an expert, so please don't follow me on this.  However, the grease looked very clean to me away from the tripod joints, and just slightly darker around the needle bearings.

 

The greasing tool is similar to a wheel bearing greaser which forces the old grease out of the bearings and new grease in.  I wipe my tripod joints clean (no parts cleaner), and then use the greaser to push new grease into the needle bearings of each tripod roller joint.  Uses about 15 grams per axle end, so 60 grams total which costs about $15. 

 

One could use their fingers to do the same thing as the tripod greasing tool, but it will take longer, waste grease, and won't be as effective in pushing out the old grease and pushing in new grease, which is what needs to be done.  It is the same concept as the wheel bearing example -- it is much simpler and better to use a greaser because it has much more pressure, is more precise, and uses less grease than trying to work the grease into a bearing by hand.

 

One other thing to note.  When you re-grease the tripod roller joints, you are also inspecting each roller for wear and early indication of failure.  

 


   
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DavidF
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Tripod joint greasing tool.  Fits snugly over the roller joint, has a grease gun fitting on the back. 

image

   
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Rod Bender
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@davidf  - Thanks David - very helpful.  One further question.  When you mention the 'service interval' recommended on these joints at 10 hours (and that you had run to 20 hours) - are you referring to 'engine run time' or 'engine load time'?  For me it makes close to 40% difference (due to the sprint races I do being less than 15 minutes in duration, so warm-up, etc represent a relatively large % of the total) 


   
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DavidF
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@rjbender

Rod I am using run time but you make a good point.  The manual says "every 10 hours of running"  which probably means in gear and rolling.

 

I have heard of more frequent driveshaft failures on SR10, and this is why I suggested using tripod joint grease instead of CV joint grease.  I believe the driveshafts are the same on the SR10 as the SR3, so my guess is that the extra rotational speed or torque or both cause a lot more heat in the tripod joints.


   
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Dan Millsaps
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David, you bring up an interesting point about the actual rollers.  I watched a local Radical dealer service an axle at their shop to learn before I got my car.  I have subsequently done my own axle service two times with the GKN tripod grease.  However, they simply open boot, clean out all old grease, wipe everything clean, visually inspect the rollers, then apply ~80 grams of new grease into the cup.  They make zero attempt to regrease the individual rollers by hand or the tool.  Interesting.


   
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John Parsons
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@davidf Seems like the tool can be a real time-saver over my method of working the grease into place via hand. My guess is that the SR10 and SR8 use the same diameter tripods (bigger than the SR3), but I don't know that for sure. 


   
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John Parsons
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@raider89 Right! If you read the actual procedure (from one of the guides here in the Resource Library), it says nothing about working grease through the rollers. Just wipe everything clean, put new grease in the cups, and reassemble. 


   
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Clark Darrah
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@parsonsj For what it's worth when I was talking to a Radical tech about the repacking process, they emphasized getting grease in the rollers.  They had a special tool that they use to do this but I don't believe it's the same as what David posted.  I'll take a picture of it next time I'm at their shop.


   
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Brian Degulis
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Good information. I really appreciate it when someone takes the time to post what the've learned and lets you know where to get what's needed.

One my 2021 SR10 and the new 2022 I just got I've had the same problem the CV or tripod boots fail. Everyone I've talked with an SR10 has also had the same problem. The right side boot on my new car failed in 2 hours. I found a replacement that doesn't fail it's a slightly thicker accordion style boot that's available at The Drive Shaft Shop in NC https://driveshaftshop.com. They call it a BT42. They come in kit form with grease and clamps. They're made for CV joint so you shouldn't use the grease the clamps are OK but I use 3/8" band width hose clamps because it's easier to service and they're re usable. Those are available from McMaster Carr.

CC901E84 BA4B 46E0 86C9 F32D3F7B98BA

 

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IMG 0709
IMG 0709

   
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DavidF
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Posted by: @bld

I use 3/8" band width hose clamps

That might be your problem -- the grooves in the tripod cup housing are for 7mm clamps.  You are using 9.5mm wide clamps which is not the original clamps.


   
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