Guy, You will need to remove the brake assembly/spacer etc to remove the wheel and tire and to replace or service the bearing.
MLS On Mon, Aug 17, 2015 at 5:51 AM, Guy Audenaerde <[email protected]> wrote: > I found a more detailed drawing of the wheelassembly, i think this might > help, unfortunately the left side is not completely in the picture... > I did not loosen or remove the bolts holding the brakeassembly to the > wheelfairing, but read in the mails that this is compulsory for good result. > Is it necessary to remove the brakeassembly in order to get the wheel out > of the fairing once the axle is removed? > I was thinking to combine the special extracting tool with the CO2 method. > I was told to heat the axle from the inside with a very mild flame to > about 60 degrees celsius and let the warmth soak into the outer spacertubes > during 20 minutes. > Once these spacertubes are warm ( and expanded ) one should rapidly cool > the axle with Co2 or other cooling gas/liquid in order to make it shrink in > diameter, thus freeing it from the > expanded outer spacertubes. > I start work on the extractor-tool, > Guy > > > *-------Oorspronkelijk bericht-------* > > *Van:* salto <[email protected]> > *Datum:* 17/08/2015 5:33:46 > *Aan:* [email protected] > *Onderwerp:* RE: [DOG mailing list] Removing wheel axle > > > When overhauling the wheel bearings of my H-36 some years ago I found that > the bearing seals were totally ineffective. The Cessna felt seal and > support washers were in place but the internal diameter of the seal was > 0.125” larger than the steel collar on which it was supposed to bear, thus > leaving an air gap all the way around the bearing where water, dust & mud > could enter. This clearance was undoubtedly the cause of our bearing > failures, especially in Australia’s dusty airfield environment. Hoffman > were not interested in this problem so we solved it by removing the Cessna > felt seal and alloy washers and substituting a neoprene automotive seal > with the same outer diameter but with a smaller internal diameter which > matched the steel collar. The seal is a readily available size & is > commonly fitted to trailer & caravan wheel bearing hubs. Other Australian > operators addressed the problem by retaining the original felt seals & > washers but replacing the steel collar with a new one machined to the > correct outer diameter to fit the original felt seals. Either approach > works quite well, but if you decide to make new collars ensure that you add > a small chamfer both sides of the internal bore of the collar to ensure it > bears only on the flat bearing faces. > > Hope this helps > > J G Viney. Dimona Lisa VH-GVQ > > > > *From:* [email protected] [mailto:[email protected]] *On > Behalf Of *Michael Stockhill > *Sent:* Monday, August 17, 2015 12:58 PM > *To:* [email protected] > *Subject:* Re: [DOG mailing list] Removing wheel axle > > > > Reviewing the H36 parts book that I have, the drawing of the > wheel/axle/brake assembly is very small scale, with few callouts for > parts. One thing that is evident is that the axle nut and lock washer are > on the outside of the wheel fairing. In the two aircraft I maintain, both > had the axle nuts inboard, with the axle inserted from outboard, resulting > in interference of the axle nut and lock washer with at least two of the > four attachment bolts that secure the brake mechanism mounts. While it may > be "prettier" to have the axle nuts inboard, it is probably best to go with > the configuration shown in the parts book. In my instance, I thought of > reassembly that way, but elected to use the countersunk screws as a minor > alteration, which we can do in this country as mechanics if we are brave > enough. > > > > Besides the four attachment bolts, there are an additional four securing a > flange for the floating brake caliper. On one or two of the four brakes I > worked on, these had to be loosened or removed in order to provide > clearance for removing the caliper. Each caliper is located by two rods of > about 7/16 diameter and an inch or so in length. If the rest of the wheel > assembly is corroded, it is probable that these are also corroded. They > can and should be cleaned and polished. The outer portion of the bore on > the cylinders is also likely to show corrosion. It is a judgement call, > but I am usually comfortable with cleaning up that corrosion with > Scotchbrite or similar products. Best to avoid steel wool as particles > will embed in the aluminum of the cylinder. Pistons can similarly be > salvaged. Braking action is significantly improved when this corrosion is > cleaned up. > > > > Removal of the bearings from their spacers may necessitate fabricating a > tool for a press or bearing puller. If I recall correctly, the ID of the > bearings is 31 or 31.5 mm, and the axle is 30 mm diameter. The spacers have > a shoulder on them. A tool would have similar configuration, with an OD of > 31 or 31.5 mm, and a shoulder, with an OD of 30 mm. > > > > Problematic was getting all the air bubbles out of the brake lines when > bleeding them (best done from the bottom). There is a flexible aircraft > hydraulic hose or line downstream of the master cylinder that can trap air > bubbles. Another more gifted Dimona mechanic told me that raising the tail > can often cause those bubbles to be displaced. This worked for me on both > aircraft, with the tail raised about three feet or so. > > > > Surely clean up any corrosion on the inside of the axles. And think of > the next guy when reassembling, using Boeshield or similar products for > corrosion control and maybe antiseize materials. > > > > If all else fails in attempting to remove the axles, consider that > Lycoming's technique for removing seized sparkplugs is to make a funnel > over the sparkplug and chill it with a blast of CO2. One could probably > shoot CO2 through the bore of the axle and shrink it away from the spacers! > > > > MLS > > > > On Sun, Aug 16, 2015 at 6:00 PM, Michael Stockhill <[email protected]> > wrote: > > A revisionist thought. If the axle is truly seized, it is likely to be > seized on the the sleeve/carrier assembly for the brake caliper as well as > the opposing bearing carrier tube. It may be best to leave it unloosened > until the axle has broken free. Sorry for the poor thinking on my feet > today. I should get out the parts book to refine my terminology. > > > > > > MLS > > > > On Sun, Aug 16, 2015 at 5:48 PM, Michael Stockhill <[email protected]> > wrote: > > Yes, those will have to come out eventually. I would just loosen them > until you get the axle out. I did find during reinstallation that if I > tightened them before everything else was assembled, that the axle would > bind at insertion. If anyone else has done brake and tire work on the > aircraft previously, you may find that the holes in the brake attach plate > have been elongated--it looks like during reassembly someone didn't get > proper alignment and just went after them with a drill bit. . On both of > our ships, that was the case. Going to the slightly oversize 1/4 inch > countersunk machine screws (vs 6 mm bolts) mitigated that a bit. Keep > track of which brake assembly goes on each side of the ship. > > > > Photos tomorrow. I took advantage of good WX to fly my PIK 20E for a > couple hours, and did the shuffle/dance to drag my Aztec out of the hangar > for test flight after maintenance. > > > > Cheers, > > > > On Sun, Aug 16, 2015 at 5:36 PM, Nils Beck <[email protected]> wrote: > > Did you also remove the 4 bolts that attach the brake to the wheel fairing? > > Best regards > > Nils Beck > > > > > On 16.08.2015 14:18, Guy Audenaerde wrote: > > My Dimona H36 Mk2 ser. 36267 build in 1988, equipped with Sauer S2100-1ss1 > has 4550 hours on the airframe. > > It is three years in my ownership and i suspect that the maintenance of > the main wheelbearings is urgently due. > > When i jack up the wheels and rotate the wheels they emit a "grinding" > noise and have a lot of play. > > Question: can someone give me a detailed procedure for removing the axle > and overhauling the wheelbearings. > > I removed the locking nut on the outside of the wheelfairing but did not > succeed in getting the axle out of the fairing, > > despite carefull tapping on the extremities with a hardwooden block. > > I suspect that the pipes that hold the bearings in place are froozen on > the central axle and prevent this axle of sliding out of the fairings; > > > > Awaiting 'instructions' > > Guy Audenaerde > > > > > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > *GRATIS animaties voor je e-mail* > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > *Klik hier!* > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150816> > > > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > GRATIS > animaties voor je e-mail > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > Klik > hier! > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > <http://www.incredimail.com/?id=621163&did=10501&ppd=2842,201206281824,19,1,1&rui=146739762&app_test_id=0&sd=20150817> > > > --------------------------------------------------------------------- > You are subscribed to the Dimona Owners Group mailing list. > To unsubscribe, send email to: [email protected] >
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