Normal Coolant Temparaure, and Rear brake lever Position

Hi to all and thank you for the reply's to my introduction.
As I said my son bought a 2002 SW with 172,498miles on it, in need of some TLC.
I have rebuilt the panels and checked over the engine and drive train. We had a problem on its first run out in that when running about it was all right but when we got home it boiled over and shot coolant everwhere .
Since then I have changed the Radiator, Waterpump and Thermostat, (the old rad was blocked and the waterpump all gunged up).
The Coolant system has been flushed and rebuilt and then I had a lot of trouble bleeding the air out ( had to disconnect the inlet manifold cooling pipe in the end to bleed the system) Any way after a good 30 minutes running on its stand and also the Radiator fan cutting in and out the temparature gauge seems to stop at the third segment mark (although when the wind blew into the bike front) it dropped to the second segment mark and came back to the third when the wind dropped.
So my first question is?  is this the normal position for the SW temp to be.

My second query is the rear brakes was buggered and so I replaced the rear disc, caliper and all the brake pads ( front and back) I have changed all the brake fluid to new and using a vacuum bleed kit have bleed all the brakes.
The front is brake is now excellant
The rear is another matter, I know the rear is a combined system and first I bleed the front single piston followed by the rear twin pistons and still the rear blake handle feels soft and touches the handle bar grip when braking.
Next I replaced the master cylinder seals and pistons but still have the same result
So my second question is? is this normal for the SW or do I have still have a problem.
I have rebuilt many an old car and motorbike but not come across this type of soft feel brake lever before so any help or explanation would be gratefully received
regards Denzil

I believe I replied to your brake question in your first post but I've noticed the brake lever for the rear brakes come back so much because it has to engage the second switch to allow the starter to run. It does feel softer than the front brakes. Are you having a problem with the engagement of the rear brakes? Does the brake lever hit the handlebars when trying to stop or just when you're sitting still? If it's hitting the handlebars when trying to stop you may have a problem but if it only when you're sitting still I believe you're alright.

I assume you have a service manual?
If you follow the brake bleeding procedure (upper front nipple first, lower front nipple second, rear nipple third), then there should be no reason why the rear brake should feel spongy, and for sure the lever shouldn't contact the handlebar on application.

Also, the radiator bleed method in the manual works perfectly.

That your temp gauge fluctuates between two and three bars seems a bit odd. But it also seems that you have addressed the cooling system as best as possible. I've never seen my gauge to vary off of three bars and I do ride in temps as low as into the mid 40°F.

Regarding the rear brake; they always seem spongy when compared to the front brake. If the rear brake stops you then I wouldn't be overly concerned about the brake system as a whole.

Tim

Hi thanks for the reply.
I don't have a service manual, and at the moment in the UK including P&P £60 seems a bit steep just for a manual.
Thank you Cosmic jumper for the info, The Temparature gauge reading at 3 segments is in the normal area on the gauge.
Thank you to Model28a and Big Bird for your help. The brake lever hits the handlebars when applying the brakes and gives you no confidence that the brakes are fully effective, about the only thing left is to change all the flexible pipes and the master cylinder.
I looked at the brake light and starter enable switch and they make contact well before applying any braking force.
The nearest way I can think to describe the brake lever feeling is if you could imagine riding a push bike with cable operated brakes and the cables are only 1 strand thick and stretch when you apply the brakes.
In all my years of fixing up old bikes and cars this rear brake has got me scratching my head (and I'm bald enough now as it is).
regards Denzil.

Mine is normally on the third block as well

Can you build up pressure in the system by "pumping" the lever ?
Did you trickle fill the system before bleeding ?
Presumably you are aware that the left lever is a combined proportionate front & rear brake ?
Are you bleeding at the lower front nipple before bleeding at the rear nipple ?

Hi The Bern
Pumping the brake lever does not make any difference to the pressure or feel of the lever which leads me to believe the system is air free. I bled the front brake first ( top and bottom pistons on front calliper) and then front centre piston on the front calliper, followed by the rear two pistons.
I have tried first the old bleeding method on just pumping the brake lever to force oil through the system until the oil was clear and air free.
Next I tried a vacuum Bleed kit which creates a vacuum and suck's the oil threw the system and forces the air out.
Both methods have given the same result a spongy brake lever feeling.
The only time I have come across this feeling is once when I had my old Humber Car and one of the flexiable pipes had collapse internally and was "ballooning" under pressure hence the spongy feeling.
Something I have noticed is that the front brake lever pumps more fluid through the front brake system, than the rear brake lever does through the rear brake system (is this normal ?).
Maybe I have a dodgy rear master cylinder. As I said I'm starting to clutch at straws so I'm grateful to any help or advice that anyone can give.
I tried our local Honda dealer and was told we don't see any SW and so a big intake of breath and think of a figure,. add the date that's what it might cost to fix.
regards Denzil

Hi Denzil, if it won't pump up then air in the system seems unlikely, a lateral thought comes to mind, seeing the huge milage yours has covered I'm wondering if the disc is below minimum thickness.

I'll nip down the garage get my manual & see what Honda have to say >>>>>>>>>>>

OK, here's the official checklist

Brake System, Troubleshooting, Brake lever soft or spongy


Air in the hydraulic system
Low brake fluid level
Clogged fluid passage
Contaminated brake disc/pad
Warped/deformed brake disc
Worn brake disc/pad
Sticking/worn master cylinder piston
Contaminated master cylinder
Contaminated caliper
Caliper not sliding properly
Leaking hydraulic system
Worn caliper piston seal
Worn master cylinder piston cups
Bent brake lever


Taken from 16-3 .. FJS600 Honda shop manual for 2001 model (mine) I had a look at the general pipe layout on mine & could not see any obvious places that might trap air.
Two thoughts, first which DOT fluid number did you use (possible cross contamination between mineral & silicon types) ? is yours ABS model (mine's not) ? if so you may need to disconnect the modulator (as on some cars) to clear air in the valve block, input from an owner with ABS might help here

HTH .. Bernie

The Bern wrote:

if so you may need to disconnect the modulator (as on some cars) to clear air in the valve block, input from an owner with ABS might help here

When I last flushed the brake fluid in my ABS model, there was no need to disconnect anything.
I used a vacuum bleeder. I found the rear brake much slower to bleed; there was a lot less flow through it than either of the front nipples.

I suggest for the rear brake lever using the old fashioned "open nipple, squeeze lever to the bar, close nipple, release brake lever, add fluid to master cylinder" until there are no more air bubbles coming through, or until you have pumped 2 full master cylinder's volume of DOT4 fluid through.

Of course, you'll need a helper for this procedure. Or, if you have a Motion Pro brake bleeder or Speed Bleeders, then you can do it yourself.

Hmm...There is a brake proportioning valve. Not quite sure what it does or which caliper it serves.

Tim

That will be the left (combined) lever so serving both calipers Tim, it's how you get the 60% front - 40% rear brake effort split (passageway restriction), it will also be the reason for the reduced fluid flow that has been noticed when bleeding the rear

Edit: I just looked in the book (16-22 + 16-23) it is called a delay valve & is the only item in the brake system without an "exploded" diagram & has no service instructions.

Hi all thanks for your input.
So far I have replaced the following
New rear Brake disc
New rear Brake Pads
New Master Cylinder Piston and seals repair kit.
New rear brake lever
Reconditioned Rear Brake caliper
New Front Brake Pads
Brand new bottle of DOT 4 brake fluid.
As you see after changing that lot I'm clutching at straws now and hanging on to any advice you can give me.
I going to try and obtain a complete rear master cylinder and try it just in case I have a problem internaly,
regards Denzil

Hi Denzil

That's a very comprehensive service list, do you have a vernier caliper ? if so then the service limits for rear master cylinder components are :

Master cylinder bore ......... 11.055mm (0.4352")

Master cylinder piston ....... 10.495mm (0.4309")

Piston is measured on the collars that the seals sit against.

Not wanting to be rude here but are you certain that the master cylinder seals are mounted the correct way round ? as if not that would give the symptoms you describe, that or a failing flexible hose are the only things I can think of given the work you have already done.

I will get my scanner out this evening & try to copy the relevant pages, not sure if it will work though as it is a thick book

Hi The Bern
Thanks for the info I do have both vernier calipers and also a bore micrometer set so I'll measure the master cylinder. The master cylinder overhaul kit came with a new piston and seals also a diagram showing the seals fitting point and direction.
I have located a second hand rear brake master cylinder, that is from a 2007 breaker which only has 7,238 miles on it which will arrive on wednsday so I'll also fit that and try to see if there is any differance in the brake feeling ( I have been told there has been no change over the years to the brake master cylinders so any year will fit and work).
If this don't work we might see a rather large storm based over the midlands and then I'll try a whole new set of brake lines after a visit to the local drinking establishment (100 yards down the road, at least it's not so far to stagger back, or for them to call the good lady to fetch me)
regards Denzil

Good luck with that Denzil, hope it all works out well bud shame you are so far away or we could have tried swapping bits off mine, let us know how you get on

Problem fixed.
Okay My replacement Rear master cylinder arrived, and was promptly fitted (the one that was fitted when measured was oval in the bore by 0.13mm and also measured 11.95mm dia so was a tad oversize ). thanks for the dimensions Bern).
I blead the system using my Vacuum bleeder until the oil was all clear, STILL a SOFT FEEL to the rear brake lever.
I then re-bleed the system using the old tried and trusted Pump the lever and open and shut the bleed nipple and guess what! a lot of swear words and STILL a soft Feeling.
So I went to the Pub with my wife and we got talking to her mate.
It turns out her husband rides a Honda Blackbird which also has a combined rearfront brake system and he has also exsperianced the same problem.
An old motor bike racer told him how to cure it, it a trick they use to use on the race bikes,
You fully bleed the system and then pull the brake lever all the way back to apply the brakes hard on. Cable tie the brake lever in this position (ie. loading / pressurising the brake system and then just leave it for 24 hours. (Some how this forces any trapped air out of the system and back to the master cylinder).
I tried this and left it, and low and behold I now have a lovely rear brake lever feeling that is as solid a feeling as the front brake.:lol!:
He told me that about every six months he just cable ties his rear brake lever back for one night and ever since he has not had any problems at all.
Thank you for all the help in sorting this out and I hope this hint might help someone else out if they exsperiance the same fault.
regards Denzil

Great tip.

Many thanks for coming back to say it's fixed Denzil & for sharing the tip that finally solved the riddle

hawkeye3guns wrote:

<>
You fully bleed the system and then pull the brake lever all the way back to apply the brakes hard on. Cable tie the brake lever in this position (ie. loading / pressurising the brake system and then just leave it for 24 hours. (Some how this forces any trapped air out of the system and back to the master cylinder).
I tried this and left it, and low and behold I now have a lovely rear brake lever feeling that is as solid a feeling as the front brake.
He told me that about every six months he just cable ties his rear brake lever back for one night and ever since he has not had any problems at all.<>

Great fix for a long standing concern of members here.

But that fix kind of begs the question; Assuming that the brake reservoirs remain topped up, just where is that air entering the hydraulic system which requires the every six month squeeze to remedy? And why doesn't it happen to the front hydraulic system too?

Thanks so much for sharing that tip.

Tim

I want to add one more question to "Cosmic_Jumper's" post above (which is most interesting, by the way): Does this noted 'technique' apply to both ABS and non ABS???

Denzil thank you for the follow up and the tip.  I've heard that before and didn't remember it so I'm glad you posted it And with the proper title in this thread it should be easy to find next time someone has the same problem.  
Tim I've heard one of the reasons you need to change your fluid every two years is because water can permeate through the rubber lines. Maybe air can too.
DickO I've read on the Burgman forum that  it works the same with ABS systems, but I've never seen it first hand.

I followed this with interest. Thanks for the update...

I've run into a similar problem several times when I used to have my GW shop. I don't know for sure about the SW but on the Goldwing which looks like exactly the same front brake master cylinder, there's a very small hole between the reservoir and the cylinder bore. There's also a larger hole between the bore and reservoir about 1/2" or so closer to the lever end of the cylinder. The small port is very small and looks like a dead ended hole that doesn't go through but it has a very small hole at the bottom of the larger one. If this small port is plugged up, and it does if one doesn't keep clean fluid in the system, it will be impossible to completely bleed the brake. I used a wire from a fine wire wheel held in a vise grip to poke out the small hole. It's got to be open but you don't want to enlarge it either. I the same set up is in the GW 1100, 1200, 1500 and the 1800. That little port is important because it allows the pressure in the brake line to bleed off when the brakes get hot which prevents brake drag and it also allows any trapped air in the system up by the master cylinders to escape into the reservoir.