| Author | Message | ||
     Dedmann |
I have a theory on the fork seal failure: http://badweatherbikers.com/buell/messages/32777/359695.html?1210441884 I believe it is fork bushings. the strain from the caliper leverage during hard breaking wears them out.... this lets the stanction stretch the seals and lets fluid pass.... thoughts? fwiw- i have changed the seals 2 times in the last 1000 miles. this rebuild i scrutinized the internals heavily (granted i dont have a dial indicator). there was nearly no difference by caliper from 1 side to the other. after a test ride it still leaks. i rebuild mountainbike forks all the time at the bicycle shop i work at. the mtb forks are just as complicated and need very tight tolerances. a fork that leaks after rebuild only leeds me to the bushing (which are not replaceable in mtbs)...... (Message edited by dedmann on April 13, 2016) | ||
| Hughlysses |
I don't think it's worn fork bushings. I had to change a leaking seal on mine a while back and the bushings were perfect. I wound up having to replace the same seal just a short time later. When I looked carefully the second time, I found 2 or 3 tiny rust pits on the fork leg. I think the rough edge of the rust pit was cutting the seal. I took a flat file and gently filed the surface of the fork leg at the pit. It didn't scratch the chrome surface but it did smooth off the rough edge of the pit. I then took touch up paint and filled the rust pit, let it dry, and sanded it smooth with 1000 grit sandpaper. No leaks since. (Message edited by Hughlysses on April 13, 2016) | ||
| Dedmann |
the stanctions are buffed up from the seals, but not scratched enough to ruin the seal lips. the old seal showed no signs of failure. im at a loss here. my hang up is the internals looked and measured identical but the brake side leaked straight away. | ||
| Nillaice |
i'll agree with you on that the brake side fork tube transfers most of the stopping forces, and would be the one to leak or wear out first. let's not ignore that it's easy to install the seals upside down or to cut the lips on the tops of the fork tube during installation, on the bushing grooves. | ||
| Blakeaspencer |
Do you guys have the same problems with fork skins or similar. I think this could be a combination of the brake force, brake dust, and maybe a bent fork, or cut seals upon installation. | ||
| Griffmeister |
I just finished my fork seal repair, a couple of thoughts in my case. Mine started leaking this time last year, prolonged their life with the "Seal-Mate". Basically dirt had gotten into the seals and wore them out. Tried cleaning again last month and it was a no go. The dirt seals had split and were no longer good for anything so this was a must do job. Also had some rust pits, not many and near the bottom. Polished them out no problem. Oh, and it was my left fork that started leaking, not the brake side. Installing new oil seals, yeah, you can fit them either way, but there is a definite way to install them. If you don't have the manual, pay attention to how they came out. One YouTube video that I watched had a good idea, cover the top of the tube with a sandwich bag, grease it and slide the seal on over the bag (kind of like installing valve stem seals on an engine). This helps guide the seal and prevents the seal lips from getting cut on the sharp edge of the bushing groove. I have a better idea that I used. First, use the bag that the seal came in. It's a heavier (stronger) mil than a sandwich bag and it also fits the fork tube almost perfectly so less wrinkles to fit the seal over. Second, use fork oil as a lubricant, not grease. Fork oil is very slippery, makes the seal almost fall right on. Grease is thicker and can actually make the seal lip roll and distort when installing. One thing bothered me, well, two. When I went to back out the preload, I found that it was eight turns in, supposed to be two. I bought the bike new and this is one adjustment that I never touched, so how did that happen? The other thing, even though they were leaking, I don't think that I lost a lot of oil. I drained out just over one bottle of oil. When I filled them it took two whole bottles plus part of a third to get the proper level. Makes me wonder if there was something wrong from the beginning, they sure feel firmer now at the recommended adjustment. That one will remain a mystery. | ||
| Dedmann |
welp.... I landed a first. I nicked the seal installing it.  I am not with out flaws and there is a first for everything. I guess I did it sliding the seal on. Found this super handy suggestion from All Balls website:  I dismantled both forks and swapped bushings from left to right. Used the left seal that wasn't leaking from previous rebuild. All better. I must remember to not get cocky  | ||
| Nillaice |
electrical tape is another option to cover the machined edges | ||
| Griffmeister |
Electric tape is sticky. Like I said, the bag that the seal came in is an almost perfect fit. |
