Rebuilding Honda FVQ shock absorbers.swiftnick Page 1 March 2009 Rebuilding Honda FVQ shock absorbers. The following is my own made up procedure for dismantling and reassembling these

swiftnick Page 1 March 2009

Rebuilding Honda FVQ shock absorbers.

The following is my own made up procedure for dismantling and reassemblingthese sealed for life units. It is not endorsed by Honda or any other recognized

authority. Use at your own risk.

First job is to remove the thinmetal cap from housing gascanister housing by pryingout. I have not found a goodway to get it out withoutdamaging it yet. Depress theSchrader valve underneath todump any air pressure.

To remove the coil spring Iuse zip ties as springcompressors. Start with thespring adjuster set to itshighest setting then compressthe coils with 5 or 6 zip ties.After they are all in place youcan work round and roundpulling each one a bit tighter.


Then back off the springadjuster to fully unload thespring and remove the capetc.

Done.

Use a suitable wrench (orpunch and hammer) to loosenthe lock nut that secures thenitrogen bladder housing.


Use a pin wrench (or hammerand punch) to loosen thebladder housing then fullyunscrew and remove thehousing.

Oil will come out. I collectedtwo shocks worth of oil andtested it by recording the timefor a measured amount toflow through a fixed orifice. Itcame out as very slightlylighter weight than SAE 5 forkoil. I am guessing theviscosity drops a fraction withuse and age so I use SAE 5oil to refill units.

Rubber bladder is withinhousing.


Hold the canister in a softvice and press the aluminumcenter down to expose thesnap ring retaining it. Use asocket of suitable diameterand C clamp to do thepressing.

Once it is pressed in farenough, hook out the snapring. Then either screw avalve tool onto the Schradervalve to pull with or unscrewand remove the Schradervalve, then screw a bolt intothe threads. Pull bladderassembly out.

Thus. Now is a good time toclean and paint the aluminumhousing. Screw the Schradervalve back into the bladder tokeep crud out.


Take body of shock to benchgrinder or belt sander andgrind away rolled over crimpon top surface. BE VERYCAREFUL not to touch pistonrod as any damage to this willmake it useless.

You need to grind awayenough until you see thewitness mark of the tube ID.The tube wall thickness is1.5mm. This requires grindinga little below the top surfaceof the washer. In this picture Idid not go quite far enough.

Use a flat screw driver as apry bar to lever off thedamper adjustment. Note asthis comes off a ball bearingwill fall out. You will see aspring in the recess behindwhere the ball was but thiscan t come out until the shockis pulled apart.


Thus.

Use some kind of leverdevice to pull the shock apart.If you did not grind off enoughin the previous step the shockwont pull out but the forceyou apply trying will trash theup stop buffer inside theshock. It does take someeffort to pull the shock apartbut you should see thewitness on the ground faceshowing almost immediately.Watch out for oil to come outthe bottom as the shock pullsapart.Make sure you save thespring from the damperadjuster that will now be freeto fall out.


Shock pulled out.

If desired now is the time toclean and paint the shockbody. Also carefully removethe sharp edges around theend to the tube that resultedfrom the grinding. This edgemust be smooth and free ofburrs or it will cut the O ringon reassembly.

Separate the damperassembly by tapping theupper bearing cap off the endoff the damper tube. A flatsteel bar or similar typedevice is best suited for this.Tap one side then the otherto pull it off squarely.

Now use a 14mm socket withan extension attached orsimilar piece of tube to reachdown inside the piston tube.Make sure socket or tube hasa smooth flat end with nolumps or burrs on it.


Hold the shock tube in onehand and use the socket todrift the valve assembly out ofthe end of the tube. Theimpact is applied to the faceof a valve washer that mustbe flat to work properly. Itrashed my first one using apin drift which put a dent inthe washer.

And it s out.

The valve assembly is heldtogether with a snap ring.Once this is removed it canbe dismantled cleaned andreassembled. The O rings areMetric size: section 1.5mmInside diameter 5.5mm


Once the valve has beencleaned and rebuilt it can betapped back into the end ofthe cleaned tube. I used a ½socket here.

To disassemble the shockrod, hold the top eye with abar and use a 10mm wrenchto undo the bottom nut. Thisnit was staked in place so atread or two will be broken offas the nut comes undone.Note the retract buffer ismissing from this picture as itgot trashed during adisassembly learningprocess.


Once the nut is removed therest of the piston assemblycan be dismantled.

Note the little pin in themiddle of the picture. Thisneeds to be pulled out of theshaft after the piston headhas been slid off the shaft.

Clean up the end of thethreads in readiness forreassembly.

The DU bushing can beremoved from the upperbearing cap by tapping it outwith a 15mm OD socket orsimilar rod or tube.

Note cap is supported on alarger socket to giveclearance to tap the bearingout.

Bearing removed.


Press in a new bearing. Oilthe OD of the bearing and thebore prior to pressing it in.

These are made by Garlockunder part number:MB1410DU.

MB1410DP4 would bepreferable to DU as it has alonger life rating in shockabsorber oil but they are hardto find off the shelve.

The original seal and topwasher are discarded andreplaced by a new seal headand lower washer. The sealhead accepts a new seal anda wiper. An O ring is used toseal the OD of the seal head.

Wrap the end of the chrometube in a single layer ofaluminum tape to protect theseal from the sharp edges.Dip the wrapped end in shockoil to fully wet it then carefullywork it through the new sealassembly. Remove thealuminum tape once the sealis on the shaft.


Reassemble piston rodassembly with new seal andbearing. Note this pic showsan earlier seal option and thewasher that is locatedbetween the seal and endcap is missing.

The O rings on the centershaft are cross section1.5mm Inside diameter8.5mm.

View of piston end. Note theparts are pretty much PokeYoke and only assemble oneway.

Be carful to ensure that all thevarious discs remain centeredand do not get clamped up inthe shaft steps when the nutis tightened. Apply loctite tothreads before installing nut

Check for free movement ofthe compression adjuster andif OK, beat the end of the rodover with a hammer to fullysecure the nut. Wipe off anyexcess loctite.


Lube the ID of the tube andpiston rod end with SAE 5shock oil. Insert rod assemblyinto tube compressing thepiston ring to get it started.

Tap the assembly fullytogether by standing it up inopen vice jaws and using asocket to apply the hammerforce to the end of the tubeassy.

Finished assembly. Put it in anice clean place until you areready to install it.


Install a new O ring (crosssection 2.0mm Insidediameter 43.5mm, standardsize S44) into the lowerbladder housing. Lube O ringwith SAE 5 shock oil.

Wipe end of bladder housingthat engages with O ring withSAE 5 shock oil. Thenensuring lock nut is in placescrew bladder housing intoshock body. Screw fully inthen back out to align verticalribs on housing to face foreand aft. Tighten lock nut.

Install spring into bottom ofhousing and stand housingvertically in a vice.


Immerse end of shockassembly in SAE 5 shock oiland pump unit up and downuntil oil is pumped out aroundbearing. Keep pumping untilthe oil coming out is free ofair bubbles.

Note the small lug on the sideof the valve body. Look downinside the main shock bodyand you will see a recess atthe bottom that this needs toengage into. Slide the tubeassembly into the shockbody. (The O ring should benicely lubed from the previousoperation).


Once piston assembly is fullypressed down, Check that thelittle spring is still in thehousing at the bottom. (If notyou will have to pull theassembly back up a bit toreinstall the spring). Now halffill bladder housing with SAE5 shock oil and gently workpiston up and down a fewtimes while holding topbearing down with a screwdriver tip or similar.

Insert cleaned bladder intobladder housing. Oil shouldoverflow around bladderbefore it is fully inserted toensure no air is entrapped.Add more oil to housing ifnecessary.

Press bladder assy down farenough to uncover snap ringgroove. Install snap ring.


Pull bladder back up usingvalve tool or removeSchrader valve and screw abolt into threads to pull with.

Top off the oil in the maincylinder and then carefullywork the piston up and downabout ½ at the top of itsstroke while topping up theoil. This is to work the last ofthe air out. Lower the sealwasher down over thebearing housing.

Finish with the cylinder full tooverflowing with no more airbubbles coming up. Removethe Schrader valve core andlower the seal head into theend of the tube. The reasonto take out the valve core is todeplete any internal pressureas the cap goes in. if youdon t do this it can ride backup again.


Carefully work around theseal with a thumb nail orsimilar to ease the seal downover the edge of the tube.(This is where the seal willget cut if you did notpreviously smooth of thesharp edge and remove anyburrs). Press the seal capdown gently while working theO ring into place. Once O ringis below the edge of the tubepress the seal head fullydown into place.

I made up a clamp block tosupport the tube wall whilestaking over the edge of thetube using a hammer andpunch. I found the bestmethod was to have a helperhold the shock bodyhorizontally and slowly roll italong while I did the tapping.

Edge fully crimped over.Need to fix the paint now.


Turn shock upside down.Install the ball into thehousing (spring should still bethere) then replace the shockadjustment lever. Use a pinpunch to spread the brassaround the shock adjusterlever to secure it in place.

Reinstall Schrader valve coreand inflate bladder to 28psi.Work shock back and forth byhand checking function ofadjusters and for any oilleaks. Let sit for 24 hours andrecheck air pressure. Itshould not leak down.




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Rebuilding Honda FVQ shock absorbers.swiftnick Page 1 March 2009 Rebuilding Honda FVQ shock absorbers. The following is my own made up procedure for dismantling and reassembling these