Steering box seal replacement

Discussion in 'How To' started by matty, Jan 16, 2012.

  1. Diddymen

    Diddymen Moderator


    hmm, thought I'd reposted all of the pics in my threads, I must have missed this one.

    I'll see if I can find them on my external drive, but I've got thousands of pics so it might take a while to find the right ones!
     
    volkswombat and MrsVolkswombat like this.
  2. Diddymen

    Diddymen Moderator

    I'll have to repost a bit at a time this time, due to pic & word limits in posts ...3rd time lucky!

    Changing the seals on the steering box and re filling with oil

    First off then, I noticed in a post regarding the changes to the MOT one of which mentioned steering box leaks. As my box was removed from the bus I decided to replace the leaking oil seals before refitting.

    First things first, drain what little oil you have into a suitable container before you start.

    remove the red filler plug by carefully prying it out (it just pushes in) and be careful not to damage the O ring in the filler plug

    473 filler plug.jpg

    next, I removed the top dust cover, thinking the clip sits in a recess on the shaft I removed it before the rubber dust cover - it turned out there was no recess in the shaft for the clip so you can remove the lot together (being careful not to damage them if you haven't got replacements)-make a note of where the arrow on the dust seal is pointing

    472 seal.jpg

    with the dust cover removed you can see the extent of the leak

    474 leak.jpg

    475 leak.jpg

    the Bently manual says it is only possible to change the seal on the drop arm side but you can in fact change both. shown below are the two new seals

    476 seal.jpg


    the sizes are:- output shaft - 28x38x7, worm shaft seal - 22x32x7I originally thought there may have been a leak from around the bolts or the shim inbetween the cover, but further investigation proved it to be the seal which was the culprit

    478 bolts.jpg


    Undo the 4 bolts and carefully remove the cover, the seal should come away with it and probably the metal shim as well, try not to bang any thing inbetween the faces to separate if it does not part easily

    479 shim.jpg


    you can see the face of the metal shim still on the outer cover showing no signs of oil leaks

    On the steering box under the outer cover you should see a thrust washer/bearing retainer

    480 new.jpg


    you can take this off to clean up the area, make sure at this point to keep everything clean and avoid getting any dirt in or around the opening or bearing

    481 clean.jpg


    clean everything up, use a scraper very carefully to remove any stubborn dirt from the mating faces of the box and cover (being careful not to scratch the faces), here you can see the cover cleaned but with the old seal still in place
     
  3. Diddymen

    Diddymen Moderator

    482 seal.jpg

    The seal is tight in place so will require it to be levered out be very careful not to scratch or score the cover recess as the new seal will not seat properly and end up leaking again

    483 old.jpg


    Fill the recess of the new seal with grease (the red stuff in the pics) and put a small smear around the cover where the seal sits

    474 leakjpg.jpg


    you should then be able to push the new seal in by hand from the out side, side of the cover making sure the bottom edge is flush with the inner face of the cover

    486 in.jpg

    remove any excess grease - I used some high performance aero grade grease as that is what I had to hand

    If you are having trouble getting the seal back in then place a bit of wood over the whole seal and gently tap home making sure it goes in square

    .......and still making sure you dont get any dirt inside the box or around your newly greased seal

    I didnt feel the need to use any jointing compound or sealent on the metal gasket as it was in good condition and didnt show any signs of leaking - and it didnt use any originally.

    If you decide to use some sealer/gasket compond, make sure you keep it to the outer edges to aviod any contanination to the bearing or inners

    replace the outer cover complete with oil seal and gently tighten the 4 bolts (working on opposites like doing a cylinder head) to achieve even tightness. I did mine up by hand and then checked they were done up to 18Nm, I think I had done then tighter by hand so I set my torque wrench to 20Nm to check and left it at that

    488 bolted.jpg

    I left the dust covers off at this point whilst I did the other end, then filled up with oil and checked for leaks (then replace dust covers)


    with the input shaft seal done its time to do the output seal, its a little trickier to get out.

    to remove the out put seal first remove the dust cover.

    You will then need to pry out the old seal very carefully, the best way to do this is to use a very small screw driver or a scriber which you use to pierce the seal in the middle (between the shaft and the casing) Some oil seals have a metal insert which will require some force to pierce so go carefully

    once you have got it in, use it as a lever to ease the seal out like so....

    487 old.jpg

    just as before, be very careful not to put heavy scratches into the shaft of casing where the seal sits when prying the old seal out

    and be careful not to let any bits of the old seal or dirt get into the case or bearing.

    and with it removed you are left with......

    489 out.jpg


    .Clean out the casing where the old seal was - I use some lint free rag wrapped over the end of the little screwdriver (being careful not to rip through the rag and put scratches in casing)

    Then the same routien applies fitting the output seal as the input seal - fill the groove of the seal with grease and wipe away any excess, I didnt put any around the casing this time instead putting a smear on the outside of the seal where it will sit against the casing (and some on the inside where the shaft goes)

    next wrap some tape around the shaft splines to protect the oil seal from abrasion when re fitting

    490 tape.jpg

    You should then be able to push the seal nearly into place using finger pressure.

    It will probably go so far, then you'll have to tap the last couple of mm home

    you can get special tools to do this but I used a 32mm deep socket which fitted nicely over the shaft

    491 socket.jpg

    you can then gently tap the top of the socket to drive the seal home - making sure you insert it sqarely and evenly.
     

    Attached Files:

    Iain McAvoy likes this.
  4. Diddymen

    Diddymen Moderator

    The socket doesnt fit neatly over the seal so If using the socket method tap one side down sligtly, then adjust the socket to the other side of the seal tap that down a little.....and so on until it is insert fully like so....

    493 in.jpg

    last thing is to remove the filler plug again (hopefully you put it back after emptying the oil to prevent dirt getting in) and fill up with new oil to the bottom of the filler plug hole.

    I used EP80 for the oil and mobil28 grease for the seals

    492 oil.jpg

    Last thing to do is check for leaks before you re fit the box to the underside of your bus (as we all know how hard it is to get the drop arm off don't we ;D )

    To check for leaks all I did was to support the steering box with the output shaft facing down wards and leave for 30mins, then, if there are no leaks support it on its side so that the input shaft is the low point, leave for 30mins

    Once you are sure there are no leaks you can replace the dust seals. You may notice that, now you have a steering box with oil in it, it may feel a bit firmer ;D

    for interest, if you are thinking of changing the bearings they are:- SKF 3555 927 open cage ball races

    The input bearing should be easy enough to do but the output bearing will need a complete strip down of the steering box

    I would also recommend getting a set of internal bearing extractors and some proper bearing insertion tools if your going to change them

    above all - keep everything clean and avoid getting contamination into the box

    hope that has helped :D
     
    77 Westy and Valveandy like this.
  5. Diddymen

    Diddymen Moderator

  6. Diddymen likes this.
  7. Just found the "How to" bit. This thread will be my bible this weekend as I'm taking the steering box to refurb with the kit I bought on here. Thank you, this is an invaluable thread. I'll let you know how I get on.
     

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