(EDIT: looking at the pics again I think it might be the outer boot at the very top of the inside that has a small hole...I felt around the boot but probably didn't touch that spot) 2007 PRIUS - 350K miles I still haven't taken my passenger-side wheel bearing apart and re-installed the dust cover for the brakes. I went to look at how it was doing and noticed heavy-grease all over inside of the wheel and some of the suspension components. I replaced the passenger-side axle and that seems OK but there is heavy grease everywhere. Gotta put it off til' tomorrow but curious what to even look for? OR is it the shock-absorber that has broken from the top and shock-grease is coming down onto the wheel from the shock-absorber? seems more likely because its falling down on the suspension but not sure what shock-grease looks like. It's dark outside now but at sunset I checked underneath my car and took a few pictures.
Somewhere on the outer CV joint, there's a pinhole leak in the boot. As the wheel spins, grease gets flung all around. Posted via the PriusChat mobile app.
this pinhole must be really small. can it be repaired with any type of seal/glue or do I have to replace the axle again?
UPDATE: Took off the wheel but still can't find the hole or how so much VOLUME of grease came out without a big tear in the CV boot. As you can see there are clumps of grease and inside the wheel is coated with grease. Only thing that makes sense is it that the clamp around the CV boot became loose through a very small area the grease came out. Another problem is that my temporarily duct-taped speed-sensor came undone and its been destroyed through wear. If you've ever wanted to know what the inside of one looks like dissected....here it is.... COULD ALL THE GREASE COME OUT OF THE SPEED-SENSOR HOLE BECAUSE THE SPEED-SENSOR WAS OUT? That doesn't seem to make sense either. thankfully I have another one available on my PartsPrius but are bigger issues able to arise from this not be replaced?
couldn't find the leak so i'm just going to drive it carefully for now. only place it could seemingly come from is the top of the CV boot on the side towards the engine where the locking ring is, however I still didn't see any type of tear or hole.
Toyota sells a kit to replace that outer boot. That is where it is coming from. (Where else is there axle grease that could be flung in the observed plane?) If the OP fixes this now there won't be a problem with the metal parts of that CV axle, but wait and it could get dirty/worn, and then a simple boot replacement will not solve the problem any more.
do you have the part number by any chance? my old boot was torn (heavily) and I simply replaced the entire axle with the current one. Seems easier to replace the axle than replace the boot unless you can give me a link that suggests otherwise.
The answer is somewhere on this page: https://www.amayama.com/en/genuine-catalogs/epc/toyota-usa/prius/NHW20L/8936/chassis/4302 A whole CV axle is pricey https://parts.longotoyota.com/oem-parts/toyota-axle-assembly-4342047021 After market CV axles cost about 7 or 8 times less. Might make sense though on a car with 250k miles. Anyway, this is why one would want to replace the boot at the first sign that it is leaking grease, so that the metal parts underneath do not also need to be changed. Well, I imagine that the CV axle will wear out eventually even if the boot is intact, but failure from loss of grease is pretty quick, whereas failure from normal wear is measured in decades.
Thanks again. the perplexing thing is: 1) there is a significant loss of grease 2) there isn't any big tear in the CV boot maybe if I take it off and examine the boot more carefully I'll find the leak but still seems weird...thats why I thought maybe its coming from another direction. DISCLAIMER: this CV axle that is currently installed & leaking was pulled off by a salvage yard (I paid $20 in total for the axle) so its possible it already had a leak/already worn that was only observable once installed. tbh: maybe its time to upgrade
When the CV axle is spinning it acts like a centrifuge as far as the grease contained in the boot is concerned, with a significant outward force applied. Grease flows through a small hole very slowly just from the force of gravity, but it moves faster when the force is 1 g plus many more from the centrifugal force (yes, yes, technically that is a fictitious force and not a real force). Additionally it is often much warmer there when the car is in operation than when the car is off. Both of those factors combine to let grease out of a boot even when the defect in the rubber is small. If the grease is coming out of a pin hole the deposits may look speckled (from the accumulation of little blobs) where it ends up on the car. If there is a larger tear or it gets by the end seals that will produce bigger blobs and less of a speckled appearance. Which reminds me, I need to clean off the wheel on our Accord which still has grease all over the inside from when that CV boot failed.