Honda CX 500 Forum banner
1 - 20 of 27 Posts

·
Registered
Joined
·
3,592 Posts
Discussion Starter · #1 ·
I do own a 1982 Honda Gl 500 Silverwing , 51000 km on her clock. Resently the bike's front brakes started to "drag" - the pistons on one ( or both sides ?) does not want to release , even though I repeatedly bled the system free of old brake fluid and any air. The brake handle also stays very hard and stiff. If any one of your experienced top guys can assist with advice , you will make my day ! The only thing I can think of is that the "back" flow in the master cyllinder seems to be blocked ? :D
 

·
Super Moderator
Joined
·
23,397 Posts
Try clearing the small fluid return hole in the bottom of the master cylinder. It is quite small and may require a hypodermic.
 

·
Registered
Joined
·
240 Posts
Most likely you had a bunch of corrosion in the caliper piston seal grooves... Pick up a couple new seal kits and then preceed with scraping out the crusty aluminum oxide from inside the seal grooves... I have a air nozzle with a cone shaped rubber tip on it that I use to blow the stuck pistons out of the bores... Remove the brake pads and place a 1/2" piece of plywood between the pistons and the caliper... Then insure your hands are nowhere near the pistons when you apply the air pressure to the hole the brake line was attached to... Sometimes you have use a heat gun to heat up the pistons and then spray a bit of penetrating oil on them... I then use a C-clamp to push the piston in just a tad to sorta break it free... Then go back to the air pressure step and they should come out... Ya then can step down to thinner and thinner plywood (or really anything) to work both pistons out of their bores together... Take your time and scrape the seal grooves really well... I use a small screw driver that I bent for the purpose and an O-ring tool cause it has a sharp point on it to get the corners clean... I then put a good coating of caliper grease in the grooves prior to installing the new seals... I clean the pistons with double ought (00) steel wool and WD40 till they are clean and shiny... A bit of caliper grease on em and work em by hand back into the caliper... If ya do the plywood and air step again after the cleaning you'll immediately see the huge difference in travel resistance of the pistons... I cannot stress enough to insure no body parts are anywhere near the pistons when you hit em with the air... Get a finger in there and you'll likely end up one finger short of a full hand...
 

·
Registered
Joined
·
240 Posts
If it's a question of "do I have all my fingers still" ??? The answer is yes...
If it's a question of "Does this method really work" ??? Again the answer is yes...

If it's a question of skill, I'd like to think I possess a reasonable amount...
 

·
Registered
Joined
·
4,278 Posts
I absolutely do not have doubts in your abilities.
But the thread starter has these skills?

In another posting, we discussed how far can you (we) go with the help to repair to vehicle brakes.

A leaking water pump seal, a stretched cam chain, a broken bolt will not hurt a person, but a failed repair of a brake, can do this.
 

·
Registered
Joined
·
24,492 Posts
izak

get some help

plan on buying a new master cylinder

having your calipers cleaned brake lines flushed or replaced and the new master fitted and bled

you have not posted where you live so we dont know if there are members nearby who can competently help you

if you have not done brake work before experimenting with your life and others safety is a bad plan
 

·
Super Moderator
Joined
·
23,397 Posts
Wolfgang.... and other senior members.

Brakes are of course a touchy subject... and that brings me to this.

I am currently rebuilding a couple of sets of 38 mm calipers.

Is a how to in order? Or do we recommend a brake shop.

We should also be starting with the simplest possible solutions first.

Another possibility in addition to a blocked return hole and calipers that need cleaning, kitting and possibly new pistons is internally swollen or torn OEM brake lines. The MC makes more pressure than the return pressure so the brakes stick on.

Troubleshooting is as simple as knowing which union to crack to let off the pressure. If cracking the unions doesn't slacken the binding brake you are left with the caliper. Which is quite likely with twinpots admittedly.
 

·
Registered
Joined
·
4,278 Posts
Worthful link, MurrayF.


@all: Please follow this link


IMPORTANT !
BEFORE YOU GO ON;
PLEASE READ
*THIS*.

I may be stepping out of line here folks,but i feel i must say this:-

Although the members of this club strive to help the fellow members/guests, ANY MECHANICAL tasks you/anyone takes upon themselves as a result of a posting/topic in the forums must be ABSOLUTELY CLEAR that the admin(Try) moderators,or ANY OTHER MEMBER, WILL NOT BE HELD RESPONSIBLE FOR ANY DAMAGE howsoever caused............THIS IS NOT A REFLECTION OF ANY MEMBERS GOOD CHARACTER.....

we give advice as friends,and share technical tips with each other............

IF YOU DECIDE TO TACKLE A PROJECT,MAKE SURE YOU HAVE THE KNOW HOW TO CARRY THESE REPAIRS/MODS OUT.

I APOLOGISE PEOPLE IF THIS SEEMS A BIT FORWARD,BUT IN MY OWN INTERESTS+MY FELLOW MEMBERS,I FEEL I MUST EMPHASISE THIS FACT.........

IF YOU DO ANYTHING AT YOUR MACHINE AS A RESULT OF A TOPIC/ADVICE......... THEN REMEMBER PLEASE,THAT YOU DO SO ENTIRELY AT YOUR OWN RISK..... NGW MEMBERS WILL NOT BE HELD RESPONSIBLE...............

YOU ALONE will be responsible for ANY undertakings/consequences you may suffer as a result of misguidance...........IF YOU AINT SURE,DONT DO IT!!!!!!!!!!!!!!

THANK YOU ONE AND ALL..................................
Good posting from Bandanna :)
 

·
Registered
Joined
·
240 Posts
I read the original post carefully and from the wording used I concluded that he appears to understand the hydraulic dynamics of the caliper... I think he is likely to be able to successfully rebuild it using the outlined steps... If he were to have any questions then he likely would post them here and be just fine... When it comes right down to it, a caliper is a rather simple mechanical device... I would certainly hope anyone that chose to work on their own bike would have a good shop manual at the ready especially when it can be obtained for free... Between that resource and the added instruction given above, I hold out very little doubt he will be highly successful in this endeavor...
 

·
Registered
Joined
·
205 Posts
is internally swollen or torn OEM brake lines. The MC makes more pressure than the return pressure so the brakes stick on.
I have seen this first hand though not on a motorcycle. It happened to a chevy corsica, I replaced the caliper twice chasing the problem and on a trip to michigan the rotor got so hot it melted the plastic hub cap. Turned out to be the brake line going to the caliper, was acting like a one way valve not allowing the caliper to release completely. AND it can react intermittently also making it difficult to diagnose.
 

·
Registered
Joined
·
4,278 Posts
Sorry boys.:

Please do not send "likes" for my posting # 11 to my address/account.
I did not !!! write this text.
The only thing what I did was to set the link.

Send Your likes to the author Bandanna.
(But I don't know how this will be done ;-))

Gruesse
WolFgang
 

·
Registered
Joined
·
3,592 Posts
Discussion Starter · #16 ·
Thanks CXPHREAK for your insights , I did dissembled and cleaned and reassembed all the parts of the master cyllinder . The openings in both the resorvoir chamer and the master cyllinder tube seems open and unblocked , and the components all seem to be fine and functional . I plan on draining the system completely and blast it clear with the aid of an air compressor , and to bleed in fresh DOT 4 brake fluid ....
 

·
Registered
Joined
·
3,592 Posts
Discussion Starter · #17 ·
Thank you Ed Z . I appreciate your advice , and I took note of the clear warnings of the force of those calliper pistons , whether they are forced outward by air or brake fluid pressure ! Fortuanately I had both callipers serviced by our local Honda branch ( Honda Central ) and I installed brand new pais of Ferodo brake pads that are the coorect size and configuration. When I unscrew the calliper's drain bolts situated at the lower portion while the units are intact on the bikes forks , the pistons seem to retract and the front weels run free while the bike is on its centre stand ... indicating that the pistons do retract when the fluid pressure is released ? Still pressure builds up again to cause draging and overheating while I take the bike out on the road for short test drives ... As I said to CXPHREAK : I plan on clearing all the brake tubings with compressed air and readminister fresh fluid, because I still tink that the pressure buils up because of a blockage somewere that prevents back flow whwn the brake lever is released ?
 

·
Registered
Joined
·
3,592 Posts
Discussion Starter · #18 ·
Thanks murryf , I did clean out all the components of the master cyllinder . All the parts seems OK and undammaged, except that the outside rubber housing around the outer stem ( the 'cnob' that is pushed in by the brake lever) is disentegrated
 

·
Registered
Joined
·
24,492 Posts
the issue could be there tiny hole called the spooge hole it lets fluid return to the master they get plugged

very simple to see if it is the master or not drive the bike till the brake drags (in some cases it will even occur in the heat of the day)

get a rag and a 14 mm or 12 mm which ever your master cylinder takes at the main line

being careful to wrap or hold the rag so brake fluid cant drip on the paint (flush with water if it happens) open and close the brake bolt slightly and slowly where the brake line joins the master

if fluid wells up and then the brake is released then the master return hole is plugged

frankly for under 50 dollars all in you can toss your old one (30 years old ) and get a brand new one and not even have dirty hands

and have piece of mind so dont rebuild it chuck it

if this does not release yoru brakes then you have either a line problem or caliper prob
 
1 - 20 of 27 Posts
Top