anti dive fix GL1800

imported post

Got to love it. New member with just 4 posts and he does this kind of work. :clapper:



GREAT WORK PAUL



Your inputs with the new pictures will make my winter project much easier plus taking a corrective action as well.



Again many thanks.



Now what is your next project? :cheeky1::cheeky1::cheeky1:



Longboater,:cooldevil:

imported post

Hi all

I am writing to update my article “Anti dive fix GL1800” posted in August 19th 2009. Firstly thanks to all that have taken the time to post a message to me, I would also like to answer a few questions that I have been asked and I’d like to explain something about the braking system at the same time because this is relevant. People have written to me and told me that ‘the anti dive should only work while operating the rear brake’ that ‘the front end should bounce freely under stationary conditions’ and ‘a drilled nickel or washer will do the same thing’ I’ve seen a thin unsealed spacer placed in a loosened brake fluid retaining part of the assembly that has left me feeling uneasy.

Stability

The reason I didn’t isolate the anti dive unit completely is because the bike needs to be as stable as possible while being ridden. Under normal riding conditions the Goldwing is like any other machine, that is to say while in a straight line, on a level road and at a set speed beyond 10-15mph, it is in its most stable condition. Input a force on the machine and it becomes less stable; this force can be applied as acceleration, deceleration or a turn. With respect to the braking effect (deceleration) all machines will transfer its weight forward, under braking, onto the front suspension making the machine less stable. Honda must have decided during the testing stages and before general sale that the bike had a large degree of dive under certain braking conditions making the bike unacceptably unstable. The upshot of this is that to prevent the bike diving so much the boffins at Honda came up with the Anti Dive Device to best deal with the problem.

How does the A.D.D. work (or not) with the brakes.

Please bear with me on this because it may explain to most what is going on with the anti dive and why it does what it does and it may save you some money, so here goes.
The linked braking system on the GL1800 is in my opinion poorly engineered. It has two front disks and one rear disk and three master cylinders. One master cylinder is connected to the hand brake lever; the second master cylinder is connected to the rear brake pedal. One of the front disk brake callipers is mounted directly to a front lower fork strut, the rear disk calliper is also mounted firmly to the rear swinging arm. The complex bit is that the other front disk calliper is mounted on a radial swivelling bracket and is prevented from moving too, far when the brakes are applied, by the third master cylinder. I don’t want to get overly complicated here so I’ll try and keep it as simple as I can. In doing so I will not involve the Delay Valve and PCV in this discussion to keep it as simple as possible.
Each of the three disk callipers have a three separate chambers or cylinders activated by either the front brake lever or the rear brake pedal nine braking cylinders in all. The front brake lever operates two cylinders on the front right calliper and one cylinder on the left front calliper and that’s it, three cylinders.
The rear brake pedal operates one cylinder in the rear calliper and also one in the front right calliper and…two cylinders in the left hand calliper four cylinders, that’s seven cylinders in total so far. This leaves two cylinders in the rear calliper unaccounted for and in a simplistic fashion I’ll try to explain what happens now. If you apply both brakes while the bike it is stationary you will not really use anything other than the seven braking cylinders. But while the bike is moving forward applying either or both brake levers activates the brakes on the previously mentioned cylinders, but now because the machine is moving the left calliper grabs the disk and because it is on a swivel bracket it will activate the third master cylinder.
This third master cylinder acts like a power servo to the remaining two rear braking cylinders and by a combination of the unmentioned Delay Valve and PCV more braking force is delivered to the remaining cylinders, the braking effort is proportional to the effort placed on the system by the rider and by the amount of pressure the floating calliper applies to the third master cylinder allowing a greater than one third of a ton bike to be stopped relatively easily.
What has this to do with the anti dive? Well the anti dive is directly connected to this third master cylinder.

The anti dive mystery and my method on how to test it.

You will find it easier to understand how the A.D.D. can be tested if you have read the previous section Carefully. Firstly while aboard the bike hold the front brake lever and pump the front suspension up and down, the suspension should move freely. If it doesn’t or it only bounced once don’t worry, it’s possible that the left calliper is gripping better than the right one at this time, this is often caused by residual brake dust on the right disk or water if its just been cleaned. If the left calliper does grip the disk better than the right one at that time for whatever reason, the left calliper will activate the Anti Dive Device this will happen even if there is the slightest movement in the third master cylinder. Try this, release the brake lever and roll the bike backwards and forwards a few inches for a couple of times then redo the bounce test but this time give the front brake lever a real big grip to prevent any possible rotation of the front wheel how ever slight, then while still gripping hard redo the bounce test and the bike should bounce freely. If this time it still refuses to bounce you may have a problem with the anti dive actuator valve but its not yet confirmed because there’s two more tests you can do. Get the bike on its main stand and get some one to sit on the rear seat to hold the front wheel off the ground, spin the front wheel and check that the wheel spins freely and the disk pads only just skim over the disks with the lightest of friction then while the wheel is spinning grab the front brake to stop the wheel dead then re-spin the wheel if you hear only light pad to disc contact then there shouldn’t be a problem there. If there is a rubbing disk then you may need to get your brakes serviced. The next test is a riding test this has to be done over a gentle speed bump or something similar that would normally be encountered on the road like entering a driveway. While the road is clear of traffic approach the speed bump or driveway at a safe speed or the normal safe speed for that hazard and apply the brakes any lever will do to slow you down before the obstruction then release the brake lever one or two feet before you arrive at the hazard. The bike should soak the hazard up cleanly if the hazard was very firm and jolted you will find that the A.D.D. is well and truly in need of attention.

Now the update on my fix

In the summer of 2008 I had a go at fixing my A.D.D and was quite proud of my fix and I told the world a year later. Since then I have had countless emails thanking me for the fix suggestion and I promised to give you an update. So here it is.
Three years on and it’s still working fine in one of our bikes but, the other bike succumbed to the dreaded damp and road salt, needless to say that I investigated further. The anti dive actuator can be stripped down cleaned and returned for duty but I’m not going to tell any one how to do this because it only takes one person to get this bit wrong and people could die and I couldn’t live with that, but return it for duty I did and I left the original fix in place and it still works as it did when I first tested it. But this time I have sealed the two units from the elements using brake quality grease as a seal. Using brake seal quality grease should prevent any problems with the piston seals if they should somehow become contaminated.

imported post

This last weekend on a very bumpy road, my front suspension got very stiff and did not loosen up until after I had stopped for a break. With 132K miles on my 2001 I decided to try this fix.

Being in the USA, I wasn't able to find any metric O-Rings without ordering them in bulk. I was able, at an ACE Hardware store, to find ones that were close and buy them individually.


For the 8.5mm X 5mm X 1.8mm I used a 5/16 X 3/16 X 1/16 #36 O-Ring
For the 10mm X 6mm X 1.8mm I used a 3/8 X 1/4 X 1/16 #5 O-Ring


I have installed them in the Bike and will see how they work.