Brake rebuild, difficult to put piston back in caliper

[Overphil]

I just put new dust seals and main seals in my disk brake on a 75 rd350 and the pistons don’t want to go back in. Gets hung up on the dust seal. I put dot3 on everything and seated the seals. Any tricks I’m missing?

Thanks!

[tacky1]

Just checking, did you clean out the slot where the seals fit, they get pretty gummed up and push out the seals that make them tight,
Are you using OEM seals..

[kobra]

I've had issues when using non-oem seals.

Some silicone paste (dielectric grease) helps them slide in easier too.

[MK]

Important note: In analogy to putting other things in interesting openings it's always mandatory to take care for adequate lubrication.

Yamaha rebuild kits usually contain a small amount of special grease for that purpose.

I also don't press the piston in "statically" but rotate it slightly around its longitudinal axis during shoving it in. Just put a pic in your head that comes up at the term "screwing".

[JonW]

LOL at Martin.... He is right tho... :)

[kpke]

Very nicely put MK

In this case definitely lubricate and rotate as you shove.

Also what tacky said. I very carefully use dental tools (acquired from the dental hygienist, yeah, sterilized before they hand them off to me) to clean all that crap out of those seal grooves.

[Overphil]

Ok, I’m with you. The dust seal groove definitely has some rust in it even though I scraped it with a dental pick. I’ll keep scraping then put some dielectric grease on her...

[Overphil]

And yes, I did get non oem seals because they were half the price and economy cycle said they work well...

[MK]

Yeah, I knew you dirty little pigs would love that kind of dirty talk

Additional note: In analogy to my above example do not use too much brute force as it may damage the rubber which we always want to avoid due to the negative consequences...

Seriously: Clean the groove perfectly. I used a dremel and this one
https://www.amazon.de/Dremel-Stahl-Drah ... B000B9N3UY
And if it doesn't fit, then bite the bullet and get Yamaha seals.

[JonW]

Like Martin I also use the Dremel wire brushes. I do alos use the pick first. When I can drop into my friends garage I also use Alumibrite to remove an left over corrosion as well.

They must be very clean before you build them up or you will be wasting your time.

Remember the corrosion builds up and pushes the seals onto the piston, sometimes allowing brake fluid to pass as well. The longer you can keep that away the better.

[Overphil]

One side is in thanks! Damaged the dust seal on the other side. The dust seal groove is still corroded on that side. Ordering a dremel and that wire brush today. I can’t believe I’ve never owned one.
Shout out to economy cycles, easier and faster than ordering parts for my 17 ktm...

[kobra]

Recently I went with an All Balls brake rebuild kit against my instinct. It turned out to be a super high quality kit and fit great - way better than the supposed Japanese-sourced seals from the internet.

[hablair]

Be careful with that Alumibrite, Jon

Hydrofluoric acid is no good for you

Get enough of it on you, it can mame and has killed, strips the calcium out of you very rapidly, unlike most other acids the body has no defence against it

As said a dremel wire brush works wonders on the seal grooves

[RZtuner]

I prefer a gentler approach. Start with a good clean in the ultra-sonic to soften everything up. Then I use a mini brass wire brush to brush off the corrosion. I buy them in 10 packs from Home Hardware for about $9. Brass is softer than aluminum so doesn't damage the alloy.

[jrodenhiser]

I prefer a gentler approach. Start with a good clean in the ultra-sonic to soften everything up. Then I use a mini brass wire brush to brush off the corrosion. I buy them in 10 packs from Home Hardware for about $9. Brass is softer than aluminum so doesn't damage the alloy.

^ Good advice, that's exactly how we do it in the shop. Lubing the seals with red rubber grease or brake fluid can help as does warming everything up.



We also now have the small square section seals for the cross over that aren't included in the OEM kit for some un-explicable reason.



link
https://www.economycycle.com/shop/yamah ... er-halves/

Here's a link to all the RZ brake parts we sell. And use coupon code RDTECH for a discount on most parts

https://www.economycycle.com/product-ca ... ha-rz-350/