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Ripped another axle/ half shaft boot. Is their a boot replacement kit?

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57
22
Exp. Type
HPDE
Exp. Level
3-5 Years
Virginia
I appear to be gaining a good collection of gt350 axles with just ripped boots. Ripped another one at Dominion 2 weeks ago after just 2 sessions. Anyone have suggestions or a boot replacement kit I can hunt down? Thank you.

20220710_182443[1].jpg
20220710_182443[1].jpg
 
If you want OEM boots, I tracked the part numbers down and they're quite peculiar. From what I can tell they used parts-binned Ford Expedition boots for only the Driver's side, which you can buy the inner and outer boot individually, where the Passenger axle appears Mustang-specific and ordered as a pair.

1657566028494.png

Passenger Side (RH)
Kit with Inner & Outer Boots - FR3Z-3A331-C

Driver Side (LH)
Outer Boot - 9L1Z-4A331-B
Inner Boot - 9L1Z-4A331-C

Other users may know about more durable options if these ripping is common, just wanted to pitch in with what I found. They're available through the dealer for what appears to be about $90 per (seemingly making the individual inner and outer twice as expensive per boot than the Mustang kit for the other axle) or about $60/pop from online retailers like Tasca, RockAuto, etc. Luckily at that price it's considerably cheaper to put an axle back in service compared to buying a new one, provided the CV didn't get anything nasty in it (Ford pictures show it coming with the necessary grease as well).

1657566511198.png
 
57
22
Exp. Type
HPDE
Exp. Level
3-5 Years
Virginia
I would agree that's super funky.
This instance it is my drivers side.
Since I have 3 axles I think I'm whiling to get really dirty to figure out the process for this.
@mwjscn To validate, your above information is in reference to a Gt350 and Gt350 axles. Juts validating.
And yes thank you for chiming in. I remember seeing somewhere individually talking about this subject about the minimal reliability of these boots. I'm fully open to a better solution.
 
I used a 2018 Mustang GT350 VIN to verify it since I didn't see you share any details here. If you'd like to check, go to parts.ford.com and enter your VIN.
1657567421716.png
Click 'Search Catalog' without entering a keyword or part number. It will ask you for your zipcode to show you prices at local dealers. You can order through this system and pick up locally, if you want. Note that different dealers in this system have different prices, so feel free to shop around if you ever want to utilize it and have multiple local dealers. You pick up at the parts counter like normal and freak out the parts guy who didn't remember placing your order over the phone or in person ;). The site also has free shipping on most smaller items, which usually comes by FedEx for me in a couple days. Sometimes it works out that their higher price+free shipping works out to be overall less expensive than the lower cost+paid shipping from online retailers for smaller yet heavier items. If the free shipping is an option, take it. It's all coming from centralized warehouses so even if you pick it up at the dealer it won't be arriving any quicker if it's not an item they stock. Zip code is used since any online sale counts as coming through that particular dealer, even if you never visited them, with their particular list prices.
Then use the search at the top of the page and input the above part numbers and the website will confirm the fit.
1657567558757.png
The Ford website doesn't display the full part numbers, like 'FR3Z', however it will allow the full part numbers as search inputs which allows you to verify the fit of full part numbers from online retailers.
 
Last edited:
57
22
Exp. Type
HPDE
Exp. Level
3-5 Years
Virginia
Mines a 2016, though I'm moderately to high confidence their were no changes over the years. I'll take a look anyhow thank you.
 
I used a 2018 Mustang GT350 VIN to verify it since I didn't see you share any details here. If you'd like to check, go to parts.ford.com and enter your VIN.
View attachment 77289
Click 'Search Catalog' without entering a keyword or part number. It will ask you for your zipcode to show you prices at local dealers. You can order through this system and pick up locally, if you want. Note that different dealers in this system have different prices, so feel free to shop around if you ever want to utilize it and have multiple local dealers. You pick up at the parts counter like normal and freak out the parts guy who didn't remember placing your order over the phone or in person ;). The site also has free shipping on most smaller items, which usually comes by FedEx for me in a couple days. Sometimes it works out that their higher price+free shipping works out to be overall less expensive than the lower cost+paid shipping from online retailers for smaller yet heavier items. If the free shipping is an option, take it. It's all coming from centralized warehouses so even if you pick it up at the dealer it won't be arriving any quicker if it's not an item they stock. Zip code is used since any online sale counts as coming through that particular dealer, even if you never visited them, with their particular list prices.
Then use the search at the top of the page and input the above part numbers and the website will confirm the fit.
View attachment 77290
The Ford website doesn't display the full part numbers, like 'FR3Z', however it will allow the full part numbers as search inputs which allows you to verify the fit of full part numbers from online retailers.

really informative post thank you!
 
Depending on which driving mode you are using and if you still have the dust shields in place is heat impacting the boots? I wonder if a high temp CV grease like Redline CV-2 would help in some way.
 
6,360
8,180
Just for fun, contact Bruce at Full Tilt Boogie Racing and see if he makes boots for these. He was neck deep in the old SN95 Cobra IRS units and I know he was transitioning to the newer cars. It would be def worth a call. He builds great stuff.
 
I also keep ripping booths on my car. Are they different on ecoboosts? Are the ford performance replacements shafts a fix? Its just that paying that price basically for booths since I only make 300whp and really dont need the extra ruggedness.

Whats causes this? The angle? the plastic from the oem unit seem really hard...
 
Bringing this one back up. The larger Oetiker clamp on the inboard boot on my drivers side slipped off the axle. Super odd.

has anyone tried the rock auto axles? Since they’re not a safety hazard if they fail the $100 price point might make it worth a shot.
 
Bringing this one back up. The larger Oetiker clamp on the inboard boot on my drivers side slipped off the axle. Super odd.

has anyone tried the rock auto axles? Since they’re not a safety hazard if they fail the $100 price point might make it worth a shot.

I ordered the Ford Performance (Mustang GT4) units. unfortunately will only test in the spring...

https://performanceparts.ford.com/part/M-3A331-GT4A
 
Interesting thanks for sharing Chuck. Please document the installation, I recall reading in the Vorschlag thread that swapping boots was quite difficult.

I just ordered and installed GT350 axles will see how they do. They're a bit longer than EB/GT axles so I'm hoping the boots will not be quite so stretched and may last longer. We'll see.
 
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Dave_W

Cones - not just for ice cream
984
1,275
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
There are a couple old-school tricks for CV joints boots that may help. One is to put a piece of small, sturdy tubing (e.g., an inch or so of WD-40 spray tube) under the boot & clamp to act as a vent if pressure builds up. The other is to tie some string or a zip-tie in one or more of the the "valleys" of the boot to keep them from ballooning out at high speed. Not sure if they'd help in this case, just throwing it out there.
 
My concern has been running the longer GT350 axles on the S550, it is odd that FP sells them as a fitment but when you buy a GT350 Brake Kit which replaces all the base S550 rear suspension with the GT350 set up, they include the longer axles in the kit. So..if the factory axles are too short for the GT350 brakes, wouldn't the GT350 axles be too long for the base S550 rear suspension? biggest question will always be what ride height away from OEM is the car set at speed (again an axle length calculation) and what is the heat soak temperature of the components coming off track? If they are cooking from heat, wrap the exhaust, if they are cooking the grease, as Dave said vent the boot and control the pressure rise inside the joint.
 
Follow up:

so I did installed the GT 350 axles on which I had to swap the original boots for the gt4’s.

I exploded both inner boots on my second session on track. It was like 40 outside and both sides broke so I highly doubt it is due to heat. My differential is cooled.
I honestly don’t know what to do anymore.

IMG_5489.jpeg
 
Follow up:

so I did installed the GT 350 axles on which I had to swap the original boots for the gt4’s.

I exploded both inner boots on my second session on track. It was like 40 outside and both sides broke so I highly doubt it is due to heat. My differential is cooled.
I honestly don’t know what to do anymore.

View attachment 86075

Chuck did you find a solution? Just tore another boot, this time outboard passenger side. Thanks.
 
Chuck did you find a solution? Just tore another boot, this time outboard passenger side. Thanks.
I ended up installing the Ford Performance axles. Been good so far. I also used the grease recommended by G-Force (makers of the axles). I had to change the boot on one side as it was rubbing on the spring.

Csx.jpg

I found these lower profile that worked perfect
DWXSA.jpg
cdsdc.jpg

BTW, if you decide to use the GT4 boots. I would suggest just using tie wraps around the shaft end. I head you could basically use nothing but a tie wrap would work well. The metal clamps hurt them:

4131.jpg2123.jpg
 

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