I noticed that the front brake lever felt a tad spongy when I was collecting the bike, so the brakes were the first job I decided to tackle.  When I stripped the brakes to examine them it was just as well – taking the condition of the brakes on an old bike for granted because they are still more or less working is not a good idea.

The hoses were removed and labelled.  A roll of white electrical tape and a permanent marker are essential items for a project like this.

The hoses were of the Goodridge braided type but they were fitted with cadmium plated banjo fittings and these were somewhat corroded.  It would be cheaper to replace the calliper and master cylinder ends with new stainless or chrome ones than to buy a new set.  Also as they were ‘bare’ braided so they would have to be covered with transparent heat shrink tubing; the ‘bare’ braided type are quite abrasive and will remove any paint they contact very quickly.  Heat shrink tubing over them still keeps the appearance but provides a smooth non-abrasive surface.

The callipers were then removed and a rough cleaning given; the paintwork on them had been damaged by brake fluid over the years and would require stripping and re-finishing.  Disassembly of the brakes is fairly simple to do – the trick is to do one at a time and keep the parts separate for each calliper.

Firstly the pistons have to be removed and the easiest way I have found to do this is to use a compressor and airline to blow them out. You need to be careful as this can be quite dangerous; it’s basically a gun that you’re operating when the compressed air is applied so wrap the calliper in a thick towel.  This also stops you getting covered in a fine mist of brake fluid!

Apply the compressed air through the brake hose orifice in short pulses (it’s safer that way) and you should hear a satisfying pop as the piston is forced out.  Mop out the cylinder with kitchen roll and use a tool such as one of those tiny precision screwdrivers to remove the seal.  Two of my pistons were heavily pitted and rusty, the other one was OK.  If there is any pitting of the pistons whatsoever they must be replaced along with new seals and boots.

On any bike that is a few years old you need to inspect the groove in which the seals sit, invariably there will be some corrosion which must be removed by carefully scraping the oxidised corrosion out especially in the corners, else the new seal will be very tight on the piston, if indeed you can get the piston in at all.  I’ve made myself tools to do this by bending the blades of a spare set of watchmakers screwdrivers to 90 degrees to turn them into scrapers – the idea being to remove the corrosion without damaging the underlying metal of the groove.

Once this was done I refitted the old seals temporarily, applied Rubber grease (more of this later) and reinserted the old pistons into the calliper bores.  They should slide in with only light pressure from your thumbs if not you haven’t got all the corrosion out.  Refitting the old pistons protects the calliper bores whilst getting the paint off the calliper bodies.

The master cylinder was also removed at this stage, stripped and checked for corrosion in a similar way.

The next stage is to remove the old paint from the calliper bodies and the master cylinder.  There is, or was in my experience, no satisfactory alternative to using a Dremel-type rotary tool and lots of patience. However since I started this project I have bought a blast cabinet – absolutely brilliant and really quick.  It’s a very messy business but great results can be achieved.

Some 10 hours later the callipers were down to the bare aluminium and after a trip through the hot wash machine (i.e. the dishwasher – don’t tell the missus, they have no sense of humour at times) looking like new.

Painting them is relatively simple except that aluminium requires a coat of self-etching primer (if you don‘t use this the paint will shortly begin to flake off), followed by the colour basecoat and finally lacquer, all this can be achieved by using aerosol cans from local motor factors, I use an airbrush for very small parts and a panel spray gun for bigger stuff because it’s more controllable and its cheaper, also the various paints can be more easily obtained.

Reassembly

Cleanliness is absolutely vital when refurbishing hydraulics and the workspace must be almost clinically clean.  Any spec of grit that gets in at this stage will compromise all the hard work done so far.  I cover the bench in newspaper and use masking tape to hold it down, if it does start to get grubby it can easily be renewed.

Only work on one calliper at a time. Assemble all the components, in my case I was replacing two pistons and refitting a serviceable one.  I used new seals and boots for all three.

Remove the old pistons using compressed air again, remove the old seals and discard them.  Give the bore and seal groove a final clean with cellulose thinners and allow it to evaporate, Wipe the calliper bore with a thin layer of Red Rubber grease.  Ensure complete coverage in the seal groove.

Red Rubber grease is fantastic stuff – specially made to lubricate rubber hydraulic components without damage.  (Other greases will definitely will rot the rubber seals and gaiters and must not be used as a substitute.)  The special rubber grease also prevents future corrosion in the callipers and is fully compatible with the brake fluids which will be present in the bore after installation.

Once you’ve applied the grease position the new seal in the groove and make sure it is fully home.  Then apply a thin layer of rubber grease to the exposed seal face and also to the piston body.  Next place the piston in the bore and press home with your thumbs; it should only take a light pressure if the job has been done properly.  Then refit the new weather seal boot.

And that’s it; the calliper is complete and ready for refitting. I had also removed the calliper carriers from the bike for refinishing and I also inspected and lubricated the sliding pins – again use rubber grease or silicon grease, allow nothing else anywhere near brakes.

Re-fitting and bleeding

Re-fitting the callipers is the reverse process of removal.  Refit the callipers carriers and torque the bolts to the correct value.  Remount the callipers and pads to the carriers and torque the bolts to the correct value.  Lubricate the bolt threads with a small amount of copper grease but don’t let it get anywhere else.

Refit the hoses (routing them carefully) using new copper washers.  You can re-use the old ones but you will need to anneal them first by heating and quenching them; I can’t be bothered and always fit new.  Torque the banjo bolts carefully to the correct values.

Next reinstall the master cylinder, having cleaned and repainted that and fitted a service kit of new seals and boot in the same way as the callipers.

Choosing your brake fluid

A choice of brake fluids is now available.  DOT4 (glycol based) brake fluid is still the most widely used and it is also much cheaper than the newer, silicon-based DOT5 type.  DOT 4 is specified by the manufacturer for GoldWings and for most bikes, apart from Harleys which use silicon based as do all American Military vehicles.

As I see it DOT4 brake fluid has two major disadvantages: firstly it is a very efficient paint remover and if any spills during the bleeding process it will most certainly damage the new paint on the callipers and secondly it’s absorbs moisture, and so needs changing every two years to stop corrosion of the master cylinder and calliper pistons.

The newer silicon type (DOT5 but be careful, recently and confusingly a glycol based DOT5.1 has appeared on the market) does not damage paintwork, in fact if any is spilled it will actually make the paintwork shine.  And it’s not hygroscopic so does not need changing as often.  On the down side it’s about five times more expensive and it’s not compatible with all brake systems – mainly Citroen and Rolls Royce which use a special mineral based fluid,  And DOT5 fluid is said to be incompatible with the GL1800 ABS system, don’t try in on an 1800.

HondaUK Customer Services do not recommend using DOT5 on any of their bikes but I feel that’s more from having to toe the Company line rather than expertise on the subject. I’ve used silicon brake fluid in all my classic bikes for the past twenty five years and never had any problems so that is what is going in the 1100.

One final point, DOT4 and DOT5 must never be mixed in a brake system, so I would never change from one to the other unless I had completely stripped and cleaned the existing brake system.

Bleeding the Brakes

When you remove and reinstall brake components you need to bleed the system to remove any trapped air in the system because air is compressible,  If you get a spongy brake pedal or lever its usually due to air being present in the system.

A helping hand to pour the fluid into the master cylinder is useful because the fluid level must be kept up to the maximum mark during the entire process.  Always use fluid from a sealed container to top up, to avoid using fluid which has absorbed water during storage.

Bleeding brakes on a classic bike is relatively simple, the main problem being that the master cylinders are tiny and move only a small minute amount of fluid at each stroke, so it takes a long time to pump the system full of fluid.  My way round this, which I’ve used for many years, is to suck the fluid through from the calliper end use a large syringe of about 150mm in body length and a length of tubing which fits tightly on both the syringe tip and also the calliper bleed nipples.

Attach a ring spanner to the nipple ensuring to can open and close it without hitting anything, then attach the syringe hose to the nipple.  Having filled the master cylinder, crack open the bleed nipple and draw the syringe plunger out.  This introduces a partial vacuum in the line and draws the fluid through.

Once the fluid appears in the syringe, close the bleed nipple and repeat the process on the other calliper, This gets the system full of fluid again relatively easily.

Then finish off by bleeding conventionally, releasing the bleed nipples in turn while pumping fluid through from the master cylinder until there are no bubbles visible in the fluid and until the pedal or lever feels firm.

Sometimes even after any amount of bleeding you still can’t get a completely firm pedal or lever.  My advice is to leave it overnight and usually the next day the feel is firm, I have no idea why this works but it usually does, the tip was passed on to me my a mechanic mate of mine and he has no idea why it works either.

You can buy purpose-built vacuum bleeding kits which do the same thing but they’re not cheap.  I used the syringe method for years until I treated myself to a ‘Mityvac’ type vacuum brake bleeder; it’s a magic piece of kit which I wouldn’t be without now.

Wheels restoration

The wheels fitted to my GL1100 are of the Comstar type, nice wheels but a real challenge to restore as the alloy spokes have a gap between the two inside faces and the access to the hub is very tight indeed, even with an airbrush.

I had decided to colour-match the wheels (and indeed the callipers and brackets) to the new bodywork colour, whether this is the right decision only time (and reassembly) will tell.

Respraying anything successfully in my experience is a matter of 95% preparation time and 5% spraying.  Stage one for these wheels was to thoroughly clean and degrease them with Gunk or Jizer and an assortment of brushes for getting into all the nooks and crannies.  Stage two was a good wash with detergent and a pressure washer  but do not use a pressure washer if you aren’t replacing the wheel bearings; they can ’blow’ the grease out even on sealed bearings.

Stage three, after letting the wheel dry thoroughly, was to flatten the old paint finish with wet & dry emery paper or abrasive pads.  You need to achieve an overall matt finish.

Stage four is to polish the alloy to provide the basis for a good paint finish.  My method of polishing is to first to flatten the alloy with 180 grit wet & dry then go over again with 320 grit to achieve a uniform matt grey finish on wheels.  Then  I use a mop fitted to a flexible shaft and an electric drill, going down the grades of polishing compound.  Finally I mop them over with Belgom Alu, which brings them up to a mirror shine.

Polishing is a really dirty job and you end up looking like you’ve been down a pit.  Incidentally at the 180 grit stage, with patience, you can actually remove some of the marks/scratches left on the wheels by ’ham fisted’ tyre fitters over the years.

Stage five is to mask off all the areas you don’t want painted and this is quite tedious – but attention to detail is all important to the finished result. I wanted the rims and spoke edges bare so I laid on masking tape and using the edge as a guide, trimmed off the excess with a scalpel.  The masking took about 5 hours per wheel to complete.  A final ‘blow off’ with compressed air to remove dust and the wheels were ready for paint.

Stage six, painting, is the easy bit. I made a jig out of MDF so the wheel was easy to rotate.  Remember what I said earlier these wheels have four sides. Firstly a couple of light coats of self etching primer were laid on, followed by light coats of colour base until I had a uniform layer of colour.  Finally acrylic lacquer was applied, again in fairly light coats.  Bear in mind that with lacquer you work to a wet edge, there were a total of 6 or 7 coats of lacquer to achieve a satisfactory finish.  Due to the intricate shape of the wheels it’s not possible to ‘cut’ the finish with compounds after painting, so the sprayed finish is all important.

How long did it take? I estimate both wheels start to finish took in excess of 60 hours.

Clocks & Instruments

The clocks and instruments were showing their years, so they were disassembled, the chrome bowls in which the speedo and  tach sit were quite badly rusted inside so that was removed and treated with Jenolite which converts the rust into a stable compound.  Then a coat of Waxoyl was applied to prevent future corrosion.

The clock bodies were starting to show signs of rust so after masking the clock plastic faces to prevent accidental scratching, they were ‘rubbed down’ to bare metal and repainted as was the centre warning console.

The wiring was inspected and found to be in good order, on reassembly all connections were cleaned and treated with silicon grease. At the same time I took the opportunity to refinish the instrument mounting bracket and the top yoke.

In Part 3 amongst other things I’ll be covering some mechanical work on the engine along with painting it and the final drive and polishing some of the alloy engine components,

I’ll also be having some components powder coated, and getting onto painting the main bodywork, fitting new higher handlebars, cables and extending the stock wiring to suit.

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GL1100 Restoration Project Part 1