KDXRIDER.NET

1989-1992 conventional forks with .40k xr400 springs and stock valves. I think they are very simple/basic.

I want to replace the fork seals this winter. Never done this by myself.Last time a mecanic did it for me.I did the 35mm negative trick to clean the seal in place but now they are shot for real!

I have a manual. I think I will make a special tool to unscrew (hold) the cylinder unit at the bottom of the forks.Or do you have a better idea...like a common tool that I can use for this?

the manual talk of 2 other special tools.

1- a weight to separate the inner tube
2-a seal pusher (to install the new seal in place)

Do I need those 2 special tools? Or I can do the job without?

Also, can you tell me the dimention of the big allen key? I will have to buy one.

My idea is to use 10w grade fork oil.... good idea for rocky trails?

Oh any tips and advices are welcome!



thanks a bunch!

14mm for the allen key. If you can find a socket with a 14mm head and you've got access to air rachet you can just flip the fork over, compress it and spin the valve right out without making the holder. You don't need a weight to separate the tubes. Just stroke them back and forth till they come apart. A PVC coupling of the appropriate size cut in half will work great for pushing the new seals back into place. I ran 7w in my stock forks when I rebuilt them.

Ah thanks!!

So with a IMPACT air ratchet I will be able to remove the cilynder without a older?

Correct, it should just spin right out. Short bursts.

Re: special tool

I used the impact gun to remove mine as well. Remember his advice -short bursts so the inertia of the rod helps you.

Be sure and seat each part. I don't recall my KDX forks clearly but on my XR I had a ring below the seal I had to seat it first. I didn't, so it took extra effort to seat the seal. But it's not hard to accomplish the job. The hardest part was cleaning everything. My parts washer is a little bench top unit and it gets messy when I clean larger parts.

I presume you will do both forks so the oil is clean and the same level in each.

I found a black coupling at Canadian Tire to drive the seal.

A seal driver is very handy. It's split so it easily 'assembles' around the fork tube.

Spendy, but good.

Yes, there are substitutes. I know PVC has been used as a driver on the KDX shock. I don't know that a suitable PVC size works for the forks.

Going through all the trouble to replace your seals only to find they LEAK because your seal driver stinketh large doesn't seem worthwhile. That's why I got the seal driver.

I recall Tusk has them cheap on RockyMtn. Considering you don't use a seal driver too often and the quality of steel in the tool isn't of import, a Tusk tool I'll bet would work just fine.

I think the MotionPro piece is around $45.

Oops. The price went up!!




The tube separation motion is quick/sharp, not necessarily BIG! If you have to S-N-A-P them very many times, the bushings are going to be toast. Mine were.

Seal drivers are usually on e-bay. One small shop was making and selling them on e-bay for $30 each in a variety of sizes. Fair quality - I bought two different sizes.

On disassembly of the fork - BEFORE you start snapping the tubes in an attempt to pull the seal out - REMOVE the seal clip! I also like to heat the outer tube in the area of the seal with a propane torch until it is hot to the touch - helps in loosening the seal.

Like everyone said - straight forward to pull apart and assembly with a minimum of tools required. Impact wrench makes it easy for disassembly and also assembly - just need to limit forces when reassembling with impact wrench.

m0rie wrote:Correct, it should just spin right out. Short bursts.

It should but that's not saying it will!

Mine did not!

I tried making the holder but could not find a hard enough nut. Ended up taking to a shop and they did not have a proper size holder either. Ended up ordering the "Tool" from Fredette

Use PVC with your old seals to help drive the new ones in, worked fine.
Also put a sammich baggie over the end of the tube and grease it up, this will make it easier to get the seal on without cutting it

I recently found a 3 piece allen set at Autozone that included a 12, 14 &17mm socket for about $7

Harbor fright (freight for ewe Canucks) has a allen socket set I think 6 piece, includes a 14 and 17 mm. I got mine for $14 amurikun munny I believe.

Merrican munny, but chineez pot metal..

I got a REAL made in AMERICA 14mm allen by cracky!!

1. I KNOW it's made in America, 'cuz it SAYS so right on it.

2. If there was ANY question about that true fact, it's origin is further proved by another true fact...the chrome plate on the thing was flaking off before I got it home!

Re: '..just need to limit forces when reassembling with impact wrench.'

IMO and all...but the BEST way to limit said force on reassy is to not USE that impact when you reassemble it. At the VERY least, start the threads by hand.

That said, I use my pneumatic impact all the time for BV removal and assembly. I know how much air to use, how to set the impact wrench and what torque it puts out. If YOU (collectively said) know all that stuff...HAMMER AWAY!!

If you don't...use hand tools to reassemble the disassembled assembly.

Thanks!

I just found a 14mm allen key in the shop where I work and I tried to remove the cylinder valve assembly (the big bolt under at the bottom of the fork )

Even with a long metal tube in the allen key (lever) the bolt did not move.

Can we use a little heat from a propane torch? hmm I do not know if it will hurt someting so I prefer to ask!

If not ,I will open my wallet and buy a socket with a 14mm allen head

Unless somebody says otherwise, I don't think a little heat is going to hurt anything there. I'd drain the oil out first just to be sure though.

I ran mine under HOT water and it worked well

edit...for the bushing removal

Can you rent an impact someplace? Of course...that rented tool wouldn't work too well with your allen wrench....

There are o-rings on the valve.

No one talking REAL heat, right?

I vote for renting/borrowing an impact.

Harbor Freight has a 12v Impact for like $19.99

http://www.harborfreight.com/cpi/ctaf/D ... mber=92349

I tried both ways, with and without the impact gun. I will always use the impact gun now. I do turn the air down a tad and insure that I have complete trigger controll before I hit them. The slow rattle of 3-5 pops per second works well. Go to an auto repair place or tire center and see if they'll let you use it there.

That electric says it has 30-40 blows a minute. That seems rather slooooow. It also reminds me of this girl in Amsterdam....

They have electric ones too... but isn't Canada running like 176.7666 volts?

I thought 12volt was electric?