Changed brake pads tight on rotor?

[soundbeltfarm]

changed the pads on the dr tonight as they were shagged and put new ones in and they are pretty tight on the rotor i can turn the wheel by hand but it is pretty hard so something not right.
ive changed them before and they were sweet the last time i did it.
could it be the pistons are full of shit and they aren't retracting fully?
any help appreciated.

SBF

[Grahameeboy]

changed the pads on the dr tonight as they were shagged and put new ones in and they are pretty tight on the rotor i can turn the wheel by hand but it is pretty hard so something not right.
ive changed them before and they were sweet the last time i did it.
could it be the pistons are full of shit and they aren't retracting fully?
any help appreciated.

SBF

I have had same on previous bikes...just removed the backing plates but would suggest checking the pistons first as this looks like likely problem if okay last time.

[Danger]

Some pads are thicker than others if you went aftermarket. I've had some pads that were so thick I could not even get them in to use them. Remove the heat backing pad is there is one and refit it later once they have worn a little.
Also I would suggest you take things easy until you are sure they are free enough. I have seen them when the pads are too tight the brakes heat up, the fluid expands and the brakes progressively come on tighter and they get even hotter and next thing the brakes are locked on just as you try to go around a corner.:gob:

[paturoa]

Also check the pins that the calipers slide on. They can get crap in them and not retract far enough for new pads.

Not sure about your model of DR (you may have to un-bolt the whole caliper from the forks, but unlikely) Drop the wheel off and then pull the caliper off the holder thingie, clean and re-grease the pins. Prolly should also have rubber grommets to stop shit getting back in there too - check those.

[F5 Dave]

as above, but
Every so often crap builds up behind the piston as it is the lowest place to fall.

Pump the piston out & check it is clean & clean behind. Scrupulously clean it first & don't use anything silly on the seals. Easy job though. Obviously remove the pads till all back together so don't get contaminated with cleaning or whatever.

[mc4aregreat]

this maybe a little bit out of date, but i have just read about this same problem in an off road magazine, and they suggest to file the leading edge of the pads to a chamfer so the disc will centralize easier.

[soundbeltfarm]

fixed the problem.
was the little pins as was suggested.
was a mission to get apart one was o.k but the other was pretty tight.
took it for a spin out the back of whanga today and brakes went good.

[Rupe]

anyone got any more advise on this?

Put some new pads (goldfren standard) on to my brakes (nissin) to replace the old pads(nissin) as they were getting thin. My new pads now rub on the rotor a fair bit, even after a little run to see if they'd sort them selves out.

There doesn't appear to be any heat backing pad to remove, and I have cleaned the pins and pistons and followed the advise in this thread but still no joy.

I also bled the brakes as the lever feels a bit mushy, but it has since I've had the bike even though I've bled it serveral times now. But don't think this is related as there is no change on the lever from old to new pads.

Just wondering if anyone has had any experience with this before that could help.

Thanks

[F5 Dave]

ok so far a start std brakes on the GG are great. Having tried other pads the Nissins are pretty good. Interesting to hear how the Goldfrens work out, never used any (or seen any).

If the brake drags for a start try the lever adjusters (there are 2) so there is def freeplay, you can adjust back from there. esp the one on the MC as opposed to the lever will give you more grasp so will help with mushyness. However I've never felt mine was mushy. I brake 1 or 2 fingered.

Did you remove the pistons? Sometimes gunk forms behind them & prevents the pistons fully retracting. Also check the disc doesn't deflect too much when applying possibly the disc may have warped or the mounting taken a blow bending it.

[Rupe]

ok so far a start std brakes on the GG are great. Having tried other pads the Nissins are pretty good. Interesting to hear how the Goldfrens work out, never used any (or seen any).

If the brake drags for a start try the lever adjusters (there are 2) so there is def freeplay, you can adjust back from there. esp the one on the MC as opposed to the lever will give you more grasp so will help with mushyness. However I've never felt mine was mushy. I brake 1 or 2 fingered.

Did you remove the pistons? Sometimes gunk forms behind them & prevents the pistons fully retracting. Also check the disc doesn't deflect too much when applying possibly the disc may have warped or the mounting taken a blow bending it.

No I didn't remove the pistons, as I wasn't 100% sure how to. I just extended them fully and cleaned round them and lubed them. Maybe I should remove them anyone got any tips, will I lose the brake fluid?

I also took the bike for a good ride at the weekend, and the binding didn't get any better. Although the brakes felt firmer, but still mushy. The brakes were stronger, but I removed the pads when I got home and they were only really rubbing/braking with the back edge of the pads, which can't be right.

Any help would be great.

[Danger]

The sponginess can be a result of air in the line due to the fluid boiling due to the pads rubbing/binding all the time. Be sure the pins on the calipers are not rusted or take them apart and clean and lube them so the calipers move freely (ok see you have done this). Don't remove the pistons at this point.
Often bleeding will not remove air in the line.
Once you are sure the pins are clean and lubed and the caliper moves freely in and out, rotate the resorvair at the lever so that it is level, remove the resorvair cap and suck out what fluid you can with a syringe, but don't expose the plastic port with the holes to air. Replace the fluid about half way up the resorvair with Dot 5.1 fluid, then lean the bike to the left as far as you can without exposing the plastic port to air and pull the hose down so that the resorvair is at the highest point. Tap the fluid line with a screwdriver handle, pull and release the lever and watch for any bubbles that pop out of the line and through the port. I bet you find quite a few coming to the surface. Soon the lever will start feeling firm again.
Top of the fluid with more fresh 5.1 fluid just to the 3/4 point, install cap, clean any spilt fluid with a squirt of water and a rag and go riding.

Alternatively once the caliper moves freely you can back bleed the brakes under pressure from the caliper to the resorvair. Air gets trapped in the line at the high point so you need to create a straighter line to the resorvair. Some banjo bolds benefit from an extra hole drilled in them as when installed the hole in the banjo bolt is at the bottom and air gets trapped in the banjo bolt rather than released into the resorvair.

[cheese]

Hmm I might give that a try too.

[F5 Dave]

I agree about the checking the pins first (which may be the extent of the problem), but it sounds like the rear pistons are either slightly seizing or restricted from moving right back.

Pumping out the pistons is pretty easy with the pads removed the pistons are pumped (make sure fluid level doesn't drop to suck air). Then pump pistons out evenly restricting the over eager ones with spacers so they all come evenly out & get wiggly by hand. This takes some care but in this instance it is the rear ones in particular you want out. Do this over a bowl, the oil will run out when the pistons come out.

Then being scrupulously clean paper towel out the calliper & check for crud that sometimes settles in the lowest position. On such a new bike this is not as common. Also on older bikes, although maybe pos is there is a build up of gunk behind the dust & main seals, like hard dandruff. Check the M/C rubber has no rips.

The seals can be removed carefully & inspected. Then the whole lot is put back together with brake fluid as a lube & pushed home. The system will need to be bleed from scratch, but it is a good idea to replace the brake fluid every yearish so no drama.

[FROSTY]

I agree totally with dave.
The only thing I'd like to add is that sometimes aftermarket pads clearances are a bit out.Ive made it a habit to clean out all pin holes and bearing surfaces with 800 grit wet and dry paper.
I can't comment in this case but Ive had issues where there is soposed to be a shim plate fitted and its missing meaning the pads aren't sitting propperly against the disk.
The other point has already been covered off. Sometimes aftermarket pads are just too thick.

[Reckless]

just a little clarification here. There are two sets of pins.
The pins that hold the pads in place and the pins that locate each half of the caliper. The pins that both halves of the calipers slide on as you put on and release the brakes are most important. They usually have little rubber expandable boots on them. They are the most common reason for jamming brakes. They must slide freely! So both halves of your calipers can move towards and away from the disk freely.

Actually once you have the brakes apart this much it is most common for me to do the pads, check and grease all the pins, pop the pistons (if necessary), replace and reblead the fluid. Only takes about an hour.
Do it all then there is no unanswered questions.

[F5 Dave]

Arrgh, brain fart, Reckless is quite right I forgot about these (problem with having too many bikes, - - - not that there is such a thing of course in case the wife is reading). I was picturing my GasGas Trials bike calliper in my mind, I knew it was wrong but all I could think of Hebo rather than Nissin as on my EC200.

[Rupe]

thanks heaps for everyones help.

The brakes were mushy before I changed the pads, so I don't think it's from boiling the fluid.

I have cleaned the pins the caliper slides on with wire-wool, and regreased them.

I'll try popping the the pistons, and cleaning them behind them next.

Thanks for the tip of tilting the bike danger I'll try that once I've cleaned behind the pistons. By the way it states dot 3 or 4 in the manual, is it better/ok to use 5.1?

Still not sure why the pads are wearing at the rear though.

[homer]

while were talking break pads ,I used to get vesrahs
there were really good ,does anyone have bad wrap about them today or are they still a good pad to use as i will get more of them in future

[Buddy L]

Thanks for the tip of tilting the bike danger I'll try that once I've cleaned behind the pistons. By the way it states dot 3 or 4 in the manual, is it better/ok to use 5.1?

.

heres a shameless copy and past of a bit of imfor that might come in handy.



Automotive brake fluid has many responsibilities. Corrosion protection and lubrication of brake system components are only a portion of the role brake fluid must play.
All automobiles that have a hydraulic braking system must use brake fluid in order for the brake system to operate. The type of fluid used can depend on the type of vehicle and the demands of the vehicles brake system.

The two most common brake fluids used in the automotive industry are fluids that contain Polyalkylene Glycol Ether and fluid that contains Silicone or Silicium-based Polymer. Both Fluids are common but very different in regards to the manner in which they perform. Fluids containing Polyalklene Glycol Ether are more widely used and are the only fluids that should be used in racing brake systems.

Because brake systems may reach extreme temperatures brake fluid must have the ability to withstand these temperatures and not degrade rapidly.

SILICONE BASED FLUID
Fluids containing Silicone are generally used in military type vehicles and because Silicone based fluids will not damage painted surfaces they are also somewhat common in show cars.

Silicone-based fluids are regarded as DOT 5 fluids. They are highly compressible and can give the driver a feeling of a spongy pedal. The higher the brake system temperature the more the compressibility of the fluid and this increases the feeling of a spongy pedal.

Silicone based fluids are non-hydroscopic meaning that they will not absorb or mix with water. When water is present in the brake system it will create a water/fluid/water/fluid situation. Because water boils at approximately 212º F, the ability of the brake system to operate correctly decreases, and the steam created from boiling water adds air to the system. It is important to remember that water may be present in any brake system. Therefore silicone brake fluid lacks the ability to deal with moisture and will dramatically decrease a brake systems performance.

POLYGLYCOL ETHER BASED FLUIDS
Fluids containing Poly glycol ethers are regarded as DOT 3, 4, and DOT 5.1. These type fluids are hydroscopic meaning they have an ability to mix with water and still perform adequately. However, water will drastically reduce the boiling point of fluid. In a passenger car this is not an issue. In a racecar it is a major issue because as the boiling point decreases the performance ability of the fluid also decreases.

Poly glycol type fluids are 2 times less compressible than silicone type fluids, even when heated. Less compressibility of brake fluid will increase pedal feel. Changing fluid on a regular basis will greatly increase the performance of the brake system.

FLUID SPECIFICATIONS All brake fluids must meet federal standard #116. Under this standard is three Department of Transportation (DOT) minimal specifications for brake fluid. They are DOT 3, DOT 4, and DOT 5.1 (for fluids based with Polyalkylene Glycol Ether) and DOT 5 (for Silicone based fluids).

MINIMAL boiling points for these specifications are as follows:



Dry Boiling Point Wet Boiling Point
DOT 3 401ºF 284º F
DOT 4 446º F 311º F
DOT 5 500º F 356º F
DOT 5.1 518º F 375º F







Racing brake fluids always exceeds the DOT specifications for dry boiling points. Wet boiling points generally remain the same.

DOT 3 VS. DOT 4 and 5.1
AFCO's 570º brake fluid is a DOT 3 type fluid. However, it has a dry boiling point that is 52º higher than DOT 5.1 specifications, 124º higher than DOT 4 specifications and 169º higher than DOT 3 specifications. AFCO's 570º fluid meets or exceeds all DOT 3, 4, and 5.1 lubrication, corrosion protection and viscosity specifications.

AFCO's 570º racing fluid meets but does not exceed federal standards for wet boiling point specification; therefore, its classification is DOT 3. Because AFCO's 570º fluid is intended for use in racing type brake systems that undergo frequent fluid changes, exceeding federal standards for wet boiling points is of little concern. Racing brake fluids always exceeds the DOT specifications for dry boiling points. Wet boiling points generally remain the same.

WET VS. DRY BOILING POINT
The term boiling point when used regarding brake fluid means the temperatures that brake fluid will begin to boil.

WET BOILING POINT
The minimum temperatures that brake fluids will begin to boil when the brake system contains 3% water by volume of the system.

DRY BOILING POINT
The temperatures that brake fluid will boil with no water present in the system.

MOISTURE IN THE BRAKE SYSTEM
Water/moisture can be found in nearly all brake systems. Moisture enters the brake system in several ways. One of the more common ways is from using old or pre-opened fluid. Keep in mind, that brake fluid draws in moisture from the surrounding air. Tightly sealing brake fluid bottles and not storing them for long periods of time will help keep moisture out. When changing or bleeding brake fluid always replace master cylinder caps as soon as possible to prevent moisture from entering into the master cylinder. Condensation, (small moisture droplets) can form in lines and calipers. As caliper and line temperatures heat up and then cool repeatedly, condensation occurs, leaving behind an increase in moisture/water. Over time the moisture becomes trapped in the internal sections of calipers, lines, master cylinders, etc. When this water reaches 212º F the water turns to steam. Many times air in the brake system is a result of water that has turned to steam. The build up of steam will create air pressure in the system, sometimes to the point that enough pressure is created to push caliper pistons into the brake pad. This will create brake drag as the rotor and pads make contact and can also create more heat in the system. Diffusion is another way in that water/moisture may enter the system.

Diffusion occurs when over time moisture enters through rubber brake hoses. The use of hoses made from EPDM materials (Ethlene-Propylene-Diene-Materials) will reduce the amount of diffusion OR use steel braided brake hose with a non-rubber sleeve (usually Teflon) to greatly reduce the diffusion process.

THINGS TO REMEMBER
Brake fluids dry boiling point is more important then wet boiling point when used in a racing brake system.
Passenger cars very rarely will undergo a brake fluid change making the wet boiling point more important.
Racing brake system fluid is changed often and a system with fresh fluid will most likely not contain water.
Because of this, racers should be concerned with the dry boiling point.
Racing fluid exceeds DOT 3, 4, and 5.1 dry boiling point specifications.
Never use silicone based fluids in racing brake systems.
Using racing brake fluid will increase performance of the braking system.
Never reuse fluid. º Never mix types or brands of brake fluid.
Use smaller fluid containers that can be used quicker.
If fluid remains in container be sure to tightly seal and do not store for long periods of time.
Purge system (complete drain) and replace fluid often.
Immediately replace master cylinder reservoir cap following any maintenance.

[Reckless]

thanks heaps for everyones help.

The brakes were mushy before I changed the pads, so I don't think it's from boiling the fluid.

I have cleaned the pins the caliper slides on with wire-wool, and regreased them.

I'll try popping the the pistons, and cleaning them behind them next.

Thanks for the tip of tilting the bike danger I'll try that once I've cleaned behind the pistons. By the way it states dot 3 or 4 in the manual, is it better/ok to use 5.1?

Still not sure why the pads are wearing at the rear though.

Firstly the pads are most likely wearing at the rear because both halves are not pulling evenly. By cleaning the slide pins etc you could quite well have solved this issue.

Secondly if everything seems like its working well (returning etc) after the repairs you have done so far and there is no leaking fluid from the pistons you could Just try changing the fliud. Ie bleed them and keep bleeding until the new fliud comes through the bleed nipple. This will chase out any air and replace old moisture soaked fliud with new. That will have given them as good a service as you can without a complete strip down and as good as most brakes get anytime. That should solve your problems I would guess. Just depends on how far you are confident to go.

Dot 5.1 has a higher boiling point but we would never push or bikes to this level. But for the same cost or a few cents more why not have it in anyway.

[Subike]

Have had this problem with my XS Yamaha,
After a bit of cussing and frustration, i visited our XS web site
This is what I found
It could be of use to some of you that are having binding problems after replacing pads and or fluid

http://www.xs11.com/forum/showthread.php?s=&threadid=14

Hopefully that link will take you to a good detailed page that may help many of you when you service your brakes.
The principiles may in application differ from manufactuers, models etc
but if it helps anyone else
then good

[Subike]

this is another link for the subject of which fluid to use.
Dot 3 - 4 or 5 ?

http://www.xs11.com/forum/showthread.php?s=&threadid=1

as you will see there is a major difference that should not be over looked

[Danger]

No one said to use Dot 5.
Dot 3, Dot 4 or Dot 5.1 is the fluid to use, not Dot 5. They are different fluids.

[Danger]

Dot 5.1 has a higher boiling point but we would never push or bikes to this level.

I disagree. The rear brakes in particular, but also the front brakes on a dirt bike ridden hard get extremely hot. Think brake dragging on a long set of whoops (if you can find them these days lol), or on the brakes almost continuely in tight trees. I have boiled my rear brakes to the point that I have had no braking. The rotor turns black and smokes. I need to bleed my rear brakes every few rides (at times during a ride that places big demands on the brakes) depending on the abuse they have had. I service my brakes at least once a month.

[worm]

changed the pads on the dr tonight as they were shagged and put new ones in and they are pretty tight on the rotor i can turn the wheel by hand but it is pretty hard so something not right.
ive changed them before and they were sweet the last time i did it.
could it be the pistons are full of shit and they aren't retracting fully?
any help appreciated.

SBF

I had the same problem on my DRZ.. just pushed the pistons out and gave em a good clean with warm soapy water and a toothbrush, pushed em back in. Worked a treat!!:yes:

[Rupe]

Popped the pistons out and gave it all a good clean the other day. And although it's better than when I first put the pads in, they still rub.

Just going to ride it and see what happens. Thinking I may just buy some nissin pads at a later date.

Thanks for everyones help

[barty5]

just a thought is the rotor ture not out of shape or is the drag the whole way around when the wheel is spun freely??

[Rupe]

just a thought is the rotor ture not out of shape or is the drag the whole way around when the wheel is spun freely??

I don't think the rotor is perfect mate, but it drags the whole way round.

[F5 Dave]

If it got highly overheated it could 'cone' so it was dragging all way round say on the outer surface on the left & inner on right, but this is unlikely unless you have been motarding it. They all drag to an extent, but there is drag & drag.

[Danger]

Hmm I might give that a try too.

So what happened?:bash: