[RemMax]

Well finally got back to the Badlands off-road park yesterday for the first time since replacing rear brake shoes and axle bearing

Everything went fine (mmostly) till I checked the diffs today

The front diff had a little water as expected but when I pulled the rear fill plug it was FULL
Clear water surged out of it well before any milk oil showed up
In all the years I've had this 300 I've never seen that happen to it

Any idea where it can get that much water in it from???
RemMax

 

[retro]

There are only two ways for water to enter either diff --- through leaky seal(s) or through the vent tube. More than likely both diffs need a bearing or two... and new seals. The rear pinion bearing/seal is hidden from view inside the swingarm. You might find that is taking on water when you take it apart.

 

[fishfiles]

It could be coming from the brake drum side from a bad seal , or the left side differential seal , or the drive shaft /pinion input seal which like Retro said is inside the swing arm , water could be getting into the swing arm from the swing arm pivot bearing seal , there is a steel plate behind the bearing which blocks off the swing arm tube from filling up with water , I apply sealant to those plates before sticking them in , if the swing arm bearings are bad it can damage that plate and let water in the swing arm and two vent tubes could give you problems , the one on the brake backing plate or the one on the diff housing , it can also leak in around the brake cam shaft , there are seals on it , and the o-ring around the brake cover -----300 OEM rear ends are bad about getting water in them , keep your eye out for a 250 ES , 250 A or 350D rear end and make the swop , they do a better job of keeping water out and lasting

 

[RemMax]

The front diff seaps a little oil around the axle seals and only let's a tiny amount of water seep in desipte being sunk in water frequently

The rear however wasn't leaking at all till this weekend

I just replaced the brakes and axle bearing/seals with a set of "allballs" bearing & seal

The backing plate on the brakes has a piece missing since before I got it so maybe I should have stuck with rtv silicone instead of yamabond when I put the large oring and cover back on

I just replaced ALL the vent lines so their good
Unfortunately the drain bolt on brake plate twisted off instead of coming out
Guess I'll be pulling brake back apart again this week. ?

What's the best way to clean the diffs without tearing it down???
Kerosene or diesel fuel flush maybe??

Thanks
RemMax

 

[fishfiles]

I use diesel and hydraulic oil , I'd guess cause I am a diesel /hydraulic mechanic and both are readily available , I flush it will diesel a few times , then fill it with hydraulic oil which is thin and cheap , then make the decision of oil or grease , I am more and more preferring grease , I would say my bikes are 50/50 right now and that's 7 of them running with 8 not far off , front diffs , rear diffs and transfer cases , I have never blown up a diff since I started greasing them , I have blown them up on oil , you still need to keep up on it and when the bearings start going out then change them before disaster occurs ----------- if it were me and the bearings were still tight and seeping some oil , I would drill and tap the swing arm tube and the fill cap of the diff and pump it full of marine grease

 

[RemMax]

Ok so I it's been raining for the past 4 days and I still haven't put the plugs back in or pulled my rear differential to see what leaked and let so much water in yet

BUT.... I have been thinking about swapping to a 350D type rear end in it despite hate a brand new ring&pinion in my current rear differential

So what's involved in swapping to a 200 or 350d rear axle assy???

Obviously gotta find the parts first and the only 350d rearend on eBay is $500 Wich I ain't got to spend on it but wondering if the other model rearends bolt to existing swingarm of if I'd have to change that to??

Not sure I wanna spend so much money on a different rear end till I see what happened in mine because it hasn't leaked till last week but I am looking at it
In all fairness I do stop with my diff's underwater quite a lot
I probably should avoid that since I have drive shafts and not a chain but sometimes ya just don't have a choice ?

Also what year 200ex, 200a or 350d rearend will work???

Thanks for the info
RemMax

 

[fishfiles]

I think I have all the models and years in my head , I know they are in threads of rear end conversions I have back when with pics -- look for 300 rear end conversion or 250 rear end ------ you can find the threads by clicking on my forum name and then go to threads by fishfiles and scroll thru the threads


1988-87 ATC250ES ( three wheeler ) , 86-87 TRX250A Fourtrax , ( 85 both atc and trx can be made to work with extra work , the swing arm needs some cutting and grinding as it is welded to the axle tubes ) , 86-89 TRX350A or D ---------- different models are different widths , the 350 is the widest , wheel spacers or rim offset make up the differences

 

[RemMax]

Thanks Fish
The Big red looks like the easiest to fit but the 350 looks to be the strongest least likely to leak.

I'll have to look at my 350d and see what's it would take to make it fit but think I'm gonna try to seal my own rear first
I don't use my quad for a lot of mudding and can limit sitting in the pond with it so if I can get it to seal like it was before may just stick with it.

Out of couriosity have any of y'all ever tried to machine tubes to extend rear housing and move axle bearing further towards outter end???
I just happen to have a huge lathe and am wondering about machining a new carrier without the brake drum in it(??)

Have to look at bike again but I definitely have more time than $$$
Especially with eBay prices for rear ends. ��

Thanks for the info
RemMax