[VStarArizona]

Replacing the front brake pads are on my list of things to be done to the bike. I have replaced them before on multiple bikes and am quite familiar with the process, however have never dealt with a "Shim" before.

On the parts list (Partzilla parts exploded view) it shows a "Shim" on the inboard side of each caliper behind the brake pad, only the inboard side (item 12 and 22 shown).

I have watch at least two YouTube videos on front brake pad replacement on the V-Star 1300 and nowhere is mentioned or shown a "shim". I contacted one of the authors of the videos and he did not seem to know anything about them. He shows the front caliper removal and the pads removed and replaced but again, no "shim" present or shown or discussed. The same is true of the other Video, except my contact to him.

Here is the question: What is the "Shim" for and is always required or is it an "as needed item" in certain circumstances? I suspect that when i pull the old pads off there will be no shim as this will be the second time the pads were replaced.

What exactly is the deal with the "Shims" in this case?? I was hoping someone knows. Thanks

 

[Jo hart]

My shim was in when I replaced my pads, so back in they went. I've also seen videos (dbests ride) where they're not mentioned. I figure if they're in the diagram, they should be on the bike, but I don't know if they are necessary.

 

[VStarArizona]

My shim was in when I replaced my pads, so back in they went. I've also seen videos (dbests ride) where they're not mentioned. I figure if they're in the diagram, they should be on the bike, but I don't know if they are necessary.

Thank you, that was the person i contacted by the way, he didn't seem to know what i was talking about. They are also shown on the 2015 parts list btw.

 

[lesblank]

This is where a lot of people will not agree with me. I put anti squeal on the back of pads instead of shim, I've never had brake squeal doing this. Just a thin coat will do it. Don't get any on the friction surface. Here's my last brake job, old pads on top, new ones on bottom, ready to install.

 

[VStarArizona]

View attachment 118425

This is where a lot of people will not agree with me. I put anti squeal on the back of pads instead of shim, I've never had brake squeal doing this. Just a thin coat will do it. Don't get any on the friction surface. Here's my last brake job, old pads on top, new ones on bottom, ready to install.

View attachment 118429

Thanks Les!

 

[vito]

You probably have brake piston pliers already?

 

[VStarArizona]

You probably have brake piston pliers already?

No i don't. push them back in using the old pad to protect the pistons when i push them in, after pushing inward on the caliper to get them most of the way in before i do anything.

 

[VStarArizona]

Question

I've always pushed the caliper pistons back in like above, but i felt i was putting pressure on the system, but did it anyways. Done the rear already without issue.

Does taking the reservoir cover off help make it easier for the pistons to be pushed back in the caliper cylinders? I have always been concerned with brake fluid being ejected doing it that way.

I was thinking of using the syringe i have to suck out some of the brake fluid out of the reservoir in advance of pushing the pistons back in. I am going to bleed the brakes either way.

What is the effect of loosening or removing the reservoir cover prior to retracting or pushing the pistons back in to remove/replace pads. What happens when this is done? Thanks.

ps: really don't want to buy any more special tools

 

[vito]

No i don't. push them back in using the old pad to protect the pistons when i push them in, after pushing inward on the caliper to get them most of the way in before i do anything.

Get a set. You use them to spin the piston(s) so that you can clean all the way around. I use a toothbrush with hot soapy water. It gets the grime off. The pliers allow you to turn the piston so the hard to reach part comes around and is easier to clean.

Dry them well, and smear a dab of white lithium grease all around. I use latex gloves for the grease part, toss them and wash my hands before I handle the pads.

 

[VStarArizona]

Get a set. You use them to spin the piston(s) so that you can clean all the way around. I use a toothbrush with hot soapy water. It gets the grime off. The pliers allow you to turn the piston so the hard to reach part comes around and is easier to clean.

Dry them well, and smear a dab of white lithium grease all around. I use latex gloves for the grease part, toss them and wash my hands before I handle the pads.

Thanks for the tips. Do you take the reservoir cover off or loosen it when you push the pistons in? What is the advantage of having the tool?

 

[AlanRides]

Question

I've always pushed the caliper pistons back in like above, but i felt i was putting pressure on the system, but did it anyways. Done the rear already without issue.

Does taking the reservoir cover off help make it easier for the pistons to be pushed back in the caliper cylinders? I have always been concerned with brake fluid being ejected doing it that way.

I was thinking of using the syringe i have to suck out some of the brake fluid out of the reservoir in advance of pushing the pistons back in. I am going to bleed the brakes either way.

What is the effect of loosening or removing the reservoir cover prior to retracting or pushing the pistons back in to remove/replace pads. What happens when this is done? Thanks.

ps: really don't want to buy any more special tools

Well, FWIW, both you and @vito are far more discerning with your brakes than I am with mine. I use a C-Clamp to ram the piston back in flush (usually try to push on the cup of the piston, but I'll grab any surface available if the cup isn't accessible) without concern of pushing the brake fluid back into the reservoir. I figure that's where it came from, that's where it can go back to. I've never done more than just wipe down the piston where it is exposed before C-Clamping it back.

Not saying I'm doing it right, and I'm sure not saying I'm doing it better, but that has worked for me for multiple decades on multiple vehicles. It may have been a caveman that first taught me how to do it......

 

[VStarArizona]

Well, FWIW, both you and @vito are far more discerning with your brakes than I am with mine. I use a C-Clamp to ram the piston back in flush (usually try to push on the cup of the piston, but I'll grab any surface available if the cup isn't accessible) without concern of pushing the brake fluid back into the reservoir. I figure that's where it came from, that's where it can go back to. I've never done more than just wipe down the piston where it is exposed before C-Clamping it back.

Not saying I'm doing it right, and I'm sure not saying I'm doing it better, but that has worked for me for multiple decades on multiple vehicles. It may have been a caveman that first taught me how to do it......

My question was whether or not you guys remove or loosen the reservoir cover before pushing in the pistons, i get everything but an answer too what I asked.

In the past i've always pushed in on the caliper which partially pushed in the pistons, they i took a scraper with a long thin blade on it and used it to protect the Disc and got in between that and the old brake pad with a large screw driver to pry the pistons all the way in. Sounds like a lot of steps, but its easy.

I wanted to improve my process though, so i thought removing or loosening the cover would relieve any pressure and the pistons would easily go in, rather that have to pry. I have always been hesitant to ty it for fear of a making a mess. Hence my question.

 

[AlanRides]

I thought I implied I just pushed the piston back without doing anything else. If not, I don't loosen or remove the cover.

 

[VStarArizona]

I thought I implied I just pushed the piston back without doing anything else. If not, I don't loosen or remove the cover.

Thanks, and i have done the same 3-4 times without issue (that i was aware of).

Thinking out loud here, but doesn't that create a pressure in the system that is potentially harmful?
Wouldn't it be better to open the reservoir, remove some fluid then gently push in the pistons without the pressure of a closed system?

 

[AlanRides]

I wouldn't think it would create any harmful pressure. After filling the reservoir and closing it up the system is now closed, so any fluid that moves out of the reservoir and into the piston(s) when extending the piston(s) would create a lower pressure in the vapor space above the fluid in reservoir. Pushing the fluid back into the reservoir should just return the reservoir's vapor space to the normal atmospheric pressure it started at.

 

[VStarArizona]

I wouldn't think it would create any harmful pressure. After filling the reservoir and closing it up the system is now closed, so any fluid that moves out of the reservoir and into the piston(s) when extending the piston(s) would create a lower pressure in the vapor space above the fluid in reservoir. Pushing the fluid back into the reservoir should just return the reservoir's vapor space to the normal atmospheric pressure it started at.

Thanks for your intelligent answer. So is it safe to say that when the brake lever is pulled-in it creates pressure in one direction, toward the pads, then when the Brake lever is let go it allows fluid to go "backwards" towards the reservoir.

If that is true, as i believe it likely is, then explain to me why the pistons are difficult or require so much force to go back in?

 

[VStarArizona]

Thanks for your intelligent answer. So is it safe to say that when the brake lever is pulled-in it creates pressure in one direction, toward the pads, then when the Brake lever is let go it allows fluid to go "backwards" towards the reservoir.

If that is true, as i believe it likely is, then explain to me why the pistons are difficult or require so much force to go back in?

I was hoping that by loosening or removing the reservoir cover and removing some fluid (going to bleed anyway) that the pistons would go in so easily that it could be done by simply pushing inwards on the caliper without the use of tools of any kind, no prying, no c-clamps, just push in the caliper while its mounted on the bike.

 

[VStarArizona]

I was hoping that by loosening or removing the reservoir cover and removing some fluid (going to bleed anyway) that the pistons would go in so easily that it could be done by simply pushing inwards on the caliper without the use of tools of any kind, no prying, no c-clamps, just push in the caliper while its mounted on the bike.

It's too hot right now but i'll try my new method and report back at some point.

 

[AlanRides]

Theoretically, allowing the pressure to escape by loosening the reservoir cap (and also the diaphragm underneath it) so air can get in should allow the piston to move easier. However, the tight seal of the piston and its sealing rings may still prevent moving the piston by hand. The downside to opening the reservoir is that it allows air (with its humidity) into the system and brake fluid which will cause brake fluid degradation. That's a bigger problem on the Gulf Coast than it is in Arizona.....LOL

It won't take much of a hasty movement to burp brake fluid out of the reservoir when pushing the piston, so be careful of that.

Thanks for your intelligent answer. So is it safe to say that when the brake lever is pulled-in it creates pressure in one direction, toward the pads, then when the Brake lever is let go it allows fluid to go "backwards" towards the reservoir.

If that is true, as i believe it likely is, then explain to me why the pistons are difficult or require so much force to go back in?

The nature of the hydraulic system used creates very high pressures (300-500 PSI in normal braking) which can move the pistons with ease while your hand grip can't come close to reproducing those pressures.

EDIT: and the hydraulic fluid is metered through some pretty small holes on its way to and from the piston, so the pressure required to push fluid through those holes is higher than most folks can generate with their bare hands.

 

[VStarArizona]

I will push the pistons in with the caliper off the bike, make for easier and more complete cleaning. Already have a new can of brake cleaner. I've used a toothbrush before to scrub it out a bit. Going to remove reservoir cover/diaphragm and some fluid and push the pistons back in (after cleaning/lubing), hopefully it will be much easier, VERY SLOWLY and CAREFULLY while watching the reservoir. Silicone paste on the pins, put some in the rubber boots too. Then bleed the brakes completely, try to use as much of the new fluid up as i can. I'll Cover the fuel tank and fender with kitchen garbage bag then towel as i always have.

I already have everything. Unless i decide to use a Vacuum Bleed bottle.

Thank all for the input!