Aircooled RD Tech Forum: poxy brakes again

Author

Message

Ozzy
Club Member

AKA ozzman

Joined: 29/Sep/2007
Online Status: Offline
Posts: 200

Topic: poxy brakes again
Posted: 13/Mar/2010 at 5:45pm

im getting the right hump with my front brakes. got the bike out started first kick got a couple of miles from home binding up solid again

. i sorted this last year and they worked fine am i missing something here or what. anyone want to buy a bike

Rd400d finaly she lives and breathes.
new toy rd200 in garage awaiting rebuild.
another rd200 in garage donor bike.
no1754

IP Logged

ting
Club Member

Ireland

Joined: 16/Jun/2004
Online Status: Offline
Posts: 107

Posted: 13/Mar/2010 at 7:06pm

yeah thats happened to me also,brake pads arent releasing off disc,had to take caliper off and give good clean with pistons out, reassembled and were ok,pistons werent pushing the brake fluid back so that the brakes would release

IP Logged

Ozzy
Club Member

AKA ozzman

Joined: 29/Sep/2007
Online Status: Offline
Posts: 200

Posted: 13/Mar/2010 at 9:11pm

why would this just happen again after a few months storage any ideas anyone?

Rd400d finaly she lives and breathes.
new toy rd200 in garage awaiting rebuild.
another rd200 in garage donor bike.
no1754

IP Logged

350lc
Club Member

Joined: 27/Aug/2009
Online Status: Offline
Posts: 304

Posted: 13/Mar/2010 at 9:16pm

ozzy maybe just lack of use

rd 200
tdr 250
RD 350 LC 1981
KR1 250
gt 125 1975
gsx 750 1981

IP Logged

Johnny
Club Member

Joined: 12/Jan/2009
Online Status: Offline
Posts: 1140

Posted: 13/Mar/2010 at 9:30pm

Mark , if I was you I'd strip the caliper , remove the piston and fit new seals , its a straight forward job . You can then inspect the piston is a free fit in the caliper before fitting the seals . If that fails the only other thing is the Master cylinder which I doubt.

IP Logged

Ozzy
Club Member

AKA ozzman

Joined: 29/Sep/2007
Online Status: Offline
Posts: 200

Posted: 13/Mar/2010 at 9:38pm

johnny did all that last year and all was ok. i did have the same problem last year but sorted it all out now its just returned. pistons are new stainless ones all seals replaced and used the bike back end of last season no problem. i was so upset cos i was having a right larf up untl then.

Rd400d finaly she lives and breathes.
new toy rd200 in garage awaiting rebuild.
another rd200 in garage donor bike.
no1754

IP Logged

GAZZATT2
Moderator Group

Gooner essex

Joined: 05/Oct/2006
Online Status: Offline
Posts: 1217

Posted: 13/Mar/2010 at 9:53pm

whip the pistons out take the seals out and make sure there is no corrosion in the grooves for the seals

R1 350lc 400F 250/400f project

IT LOOKS GOOD IN A PHOTO LANCE

IP Logged

CaptainSensible
Club Member

AKA Lance

Joined: 08/Jan/2007
Online Status: Offline
Posts: 315

Posted: 13/Mar/2010 at 11:14pm

mark it will be your master cylinder, when you take the filler reservoir off there are two holes on the base one large, and one pinhole sized one, im betting the small one is blocked, its to do with the return valve for the oil to come back and release the pistons,

Why do i keep rd's

IP Logged

SupeRDel
Moderator Group

North Wiltshire

Joined: 30/Mar/2002
Online Status: Offline
Posts: 3906

Posted: 14/Mar/2010 at 7:36am

Seals around the piston have nothing to do with binding. Look at the mechanics - you have a steel piston sliding thru a rubber oil seal. Have yet to see rubber that can grip steel that hard. If it could you would never get the brake to work in the first place.

It has too be the oil in the lines staying pressurised or partially pressurised when you release the lever. There must be something still floating around in the oil that has blocked that hole again.

Take the lid and rubber off the reservoir and poke a needle down thru the oil into the little hole. Careful when doing this with a siezed brake - the squirt of fluid as pressure is released my get you in the eye.

Riding the bike a lot would make little differance - the crude was still in the system - it could appear anytime.

Give me a cider --With a straw!!!!

IP Logged

SupeRDel
Moderator Group

North Wiltshire

Joined: 30/Mar/2002
Online Status: Offline
Posts: 3906

Posted: 14/Mar/2010 at 7:46am

Just too add. My RD400 had eactly the same problem when I bought it.

I removed the whole lot and washed everything thru in a degease tank. I actuallly felt the needle brake thru the little hole blockage.

I rebuilt my brakes with all the old seals - 30 years old.
They work fine.

Give me a cider --With a straw!!!!

IP Logged

Johnny
Club Member

Joined: 12/Jan/2009
Online Status: Offline
Posts: 1140

Posted: 14/Mar/2010 at 7:57am

If the system is presurising Del , could you not prove this by just releasing it by cracking open the bleed nipple and releasing the suspected pressure. If this free's the brake off , then you've proved what the the problem is.

If it doesn't then its the caliper at fault .

IP Logged

SupeRDel
Moderator Group

North Wiltshire

Joined: 30/Mar/2002
Online Status: Offline
Posts: 3906

Posted: 14/Mar/2010 at 8:10am

Yeap - should do the same.

You would have to do this with the when you have ridden the bike and got it to seize to prove it though.

Give me a cider --With a straw!!!!

IP Logged

Ozzy
Club Member

AKA ozzman

Joined: 29/Sep/2007
Online Status: Offline
Posts: 200

Posted: 14/Mar/2010 at 2:42pm

all valid points and taken on board but i did do all this back end of last year and cured the problem so i thought. i cleaned the whole system two or three times to make sure all was well purchased new seals and pistons and it worked fine. the only thing thats different is it has been stored for a few months over the winter. i will strip and clean the system again as a matter of coarse but i have lost confidence in riding for any long distance which is pissing me off cos the bike runs a dream apart from that. oh well thanks for the advice guys. again.

Rd400d finaly she lives and breathes.
new toy rd200 in garage awaiting rebuild.
another rd200 in garage donor bike.
no1754

IP Logged

SupeRDel
Moderator Group

North Wiltshire

Joined: 30/Mar/2002
Online Status: Offline
Posts: 3906

Posted: 14/Mar/2010 at 6:26pm

First ride the bike near home till the brake binds again.

The open that bleed nipple just to let pressure out. Then see if front wheel turns freely again.

That will confirm the pressure in the system is holding the brake on.

Give me a cider --With a straw!!!!

IP Logged

Ozzy
Club Member

AKA ozzman

Joined: 29/Sep/2007
Online Status: Offline
Posts: 200

Posted: 14/Mar/2010 at 6:50pm

im 100% sure you are right del just bugging me as to why it was ok then it decides ok i dont want to work anymore.

Rd400d finaly she lives and breathes.
new toy rd200 in garage awaiting rebuild.
another rd200 in garage donor bike.
no1754

IP Logged

mgmark
Newcomer

Joined: 09/Apr/2006
Online Status: Offline
Posts: 7

Posted: 14/Mar/2010 at 9:52pm

My RD400 had this happen to the rear brakes, exactly the same thing your front brakes did. I finally found the tiny bleed hole under the reservoir hose fitting in the m/cyl body. Once cleared the brakes never pumped up again and were perfect.

As a side note, I have always re-used caliper seals after thoroughly cleaning out the caliper bodies and scraping the rust off the seals, never a problem with them.

But then I'm a cheap bastard.......

Mark

2-strokes, many cylinders

RD400E
RD250 Proddy Racer

IP Logged

Aircooled RD Tech Help 250cc and Above
Aircooled RD Tech Forum : Tech Zone : Aircooled RD Tech Help 250cc and Above

Author	Message
Ozzy Club Member AKA ozzman Joined: 29/Sep/2007 Online Status: Offline Posts: 200	Topic: poxy brakes again Posted: 13/Mar/2010 at 5:45pm
	im getting the right hump with my front brakes. got the bike out started first kick got a couple of miles from home binding up solid again . i sorted this last year and they worked fine am i missing something here or what. anyone want to buy a bike
	Rd400d finaly she lives and breathes. new toy rd200 in garage awaiting rebuild. another rd200 in garage donor bike. no1754
	IP Logged

ting Club Member Ireland Joined: 16/Jun/2004 Online Status: Offline Posts: 107	Posted: 13/Mar/2010 at 7:06pm
	yeah thats happened to me also,brake pads arent releasing off disc,had to take caliper off and give good clean with pistons out, reassembled and were ok,pistons werent pushing the brake fluid back so that the brakes would release

	IP Logged

Ozzy Club Member AKA ozzman Joined: 29/Sep/2007 Online Status: Offline Posts: 200	Posted: 13/Mar/2010 at 9:11pm
	why would this just happen again after a few months storage any ideas anyone?
	Rd400d finaly she lives and breathes. new toy rd200 in garage awaiting rebuild. another rd200 in garage donor bike. no1754
	IP Logged

350lc Club Member Joined: 27/Aug/2009 Online Status: Offline Posts: 304	Posted: 13/Mar/2010 at 9:16pm
	ozzy maybe just lack of use
	rd 200 tdr 250 RD 350 LC 1981 KR1 250 gt 125 1975 gsx 750 1981
	IP Logged

Johnny Club Member Joined: 12/Jan/2009 Online Status: Offline Posts: 1140	Posted: 13/Mar/2010 at 9:30pm
	Mark , if I was you I'd strip the caliper , remove the piston and fit new seals , its a straight forward job . You can then inspect the piston is a free fit in the caliper before fitting the seals . If that fails the only other thing is the Master cylinder which I doubt.

	IP Logged

Ozzy Club Member AKA ozzman Joined: 29/Sep/2007 Online Status: Offline Posts: 200	Posted: 13/Mar/2010 at 9:38pm
	johnny did all that last year and all was ok. i did have the same problem last year but sorted it all out now its just returned. pistons are new stainless ones all seals replaced and used the bike back end of last season no problem. i was so upset cos i was having a right larf up untl then.
	Rd400d finaly she lives and breathes. new toy rd200 in garage awaiting rebuild. another rd200 in garage donor bike. no1754
	IP Logged

GAZZATT2 Moderator Group Gooner essex Joined: 05/Oct/2006 Online Status: Offline Posts: 1217	Posted: 13/Mar/2010 at 9:53pm
	whip the pistons out take the seals out and make sure there is no corrosion in the grooves for the seals
	R1 350lc 400F 250/400f project IT LOOKS GOOD IN A PHOTO LANCE
	IP Logged

CaptainSensible Club Member AKA Lance Joined: 08/Jan/2007 Online Status: Offline Posts: 315	Posted: 13/Mar/2010 at 11:14pm
	mark it will be your master cylinder, when you take the filler reservoir off there are two holes on the base one large, and one pinhole sized one, im betting the small one is blocked, its to do with the return valve for the oil to come back and release the pistons,
	Why do i keep rd's
	IP Logged

SupeRDel Moderator Group North Wiltshire Joined: 30/Mar/2002 Online Status: Offline Posts: 3906	Posted: 14/Mar/2010 at 7:36am
	Seals around the piston have nothing to do with binding. Look at the mechanics - you have a steel piston sliding thru a rubber oil seal. Have yet to see rubber that can grip steel that hard. If it could you would never get the brake to work in the first place. It has too be the oil in the lines staying pressurised or partially pressurised when you release the lever. There must be something still floating around in the oil that has blocked that hole again. Take the lid and rubber off the reservoir and poke a needle down thru the oil into the little hole. Careful when doing this with a siezed brake - the squirt of fluid as pressure is released my get you in the eye. Riding the bike a lot would make little differance - the crude was still in the system - it could appear anytime.
	Give me a cider --With a straw!!!!
	IP Logged

SupeRDel Moderator Group North Wiltshire Joined: 30/Mar/2002 Online Status: Offline Posts: 3906	Posted: 14/Mar/2010 at 7:46am
	Just too add. My RD400 had eactly the same problem when I bought it. I removed the whole lot and washed everything thru in a degease tank. I actuallly felt the needle brake thru the little hole blockage. I rebuilt my brakes with all the old seals - 30 years old. They work fine.
	Give me a cider --With a straw!!!!
	IP Logged

Johnny Club Member Joined: 12/Jan/2009 Online Status: Offline Posts: 1140	Posted: 14/Mar/2010 at 7:57am
	If the system is presurising Del , could you not prove this by just releasing it by cracking open the bleed nipple and releasing the suspected pressure. If this free's the brake off , then you've proved what the the problem is. If it doesn't then its the caliper at fault .

	IP Logged

SupeRDel Moderator Group North Wiltshire Joined: 30/Mar/2002 Online Status: Offline Posts: 3906	Posted: 14/Mar/2010 at 8:10am
	Yeap - should do the same. You would have to do this with the when you have ridden the bike and got it to seize to prove it though.
	Give me a cider --With a straw!!!!
	IP Logged

Ozzy Club Member AKA ozzman Joined: 29/Sep/2007 Online Status: Offline Posts: 200	Posted: 14/Mar/2010 at 2:42pm
	all valid points and taken on board but i did do all this back end of last year and cured the problem so i thought. i cleaned the whole system two or three times to make sure all was well purchased new seals and pistons and it worked fine. the only thing thats different is it has been stored for a few months over the winter. i will strip and clean the system again as a matter of coarse but i have lost confidence in riding for any long distance which is pissing me off cos the bike runs a dream apart from that. oh well thanks for the advice guys. again.
	Rd400d finaly she lives and breathes. new toy rd200 in garage awaiting rebuild. another rd200 in garage donor bike. no1754
	IP Logged

SupeRDel Moderator Group North Wiltshire Joined: 30/Mar/2002 Online Status: Offline Posts: 3906	Posted: 14/Mar/2010 at 6:26pm
	First ride the bike near home till the brake binds again. The open that bleed nipple just to let pressure out. Then see if front wheel turns freely again. That will confirm the pressure in the system is holding the brake on.
	Give me a cider --With a straw!!!!
	IP Logged

Ozzy Club Member AKA ozzman Joined: 29/Sep/2007 Online Status: Offline Posts: 200	Posted: 14/Mar/2010 at 6:50pm
	im 100% sure you are right del just bugging me as to why it was ok then it decides ok i dont want to work anymore.
	Rd400d finaly she lives and breathes. new toy rd200 in garage awaiting rebuild. another rd200 in garage donor bike. no1754
	IP Logged

mgmark Newcomer Joined: 09/Apr/2006 Online Status: Offline Posts: 7	Posted: 14/Mar/2010 at 9:52pm
	My RD400 had this happen to the rear brakes, exactly the same thing your front brakes did. I finally found the tiny bleed hole under the reservoir hose fitting in the m/cyl body. Once cleared the brakes never pumped up again and were perfect. As a side note, I have always re-used caliper seals after thoroughly cleaning out the caliper bodies and scraping the rust off the seals, never a problem with them. But then I'm a cheap bastard....... Mark
	2-strokes, many cylinders RD400E RD250 Proddy Racer
	IP Logged