Author Topic: CB400F caliper piston made from Delrin:is it a good product ? (Read 6842 times)

grcamna2 · « **on:** December 24, 2011, 06:57:39 PM »

I thought I read somewhere here on the forum that there is a source for a caliper piston for my CB400F(same as the CB550 presumably??)made out of that tough Delrin material....does anyone have some practical knowledge of this caliper piston and the long term durability of it in use ? will it stand up to years of brake fluid exposure ??

Kong · « **Reply #1 on:** December 24, 2011, 07:42:32 PM »

They work just fine in automobiles, they should work in old bikes too. The fellow I got mine from was making them from stock ones from a Lincoln if I remember correctly.

Ringo · « **Reply #2 on:** December 24, 2011, 07:58:17 PM »

I believe you're talking about the phenolic pistons made by Kevin400F here? If so, they're great; perfect fit on my 550, and much lighter than stock. Hit him up...

grcamna2 · « **Reply #3 on:** December 24, 2011, 08:58:47 PM »

Ringo,
How well do they return after you let off of the brake from a hard stop ? in other words, do they slide back & forth inside the caliper when installed ? more slippery than the O.E. ??

Ringo · « **Reply #4 on:** December 24, 2011, 09:06:52 PM »

They've never stuck for me yet. Seem to work perfectly; they do slide nicely, I've had the caliper off many times for pad replacement/cleaning and they move smoothly. Can't tell you how they compare to stock because I swapped the corroded steel stock one out without a second thought. But brake function has been perfect.

grcamna2 · « **Reply #5 on:** December 24, 2011, 10:05:55 PM »

How much $ does he get for one ?

88blkiroc · « **Reply #6 on:** December 24, 2011, 10:12:05 PM »

I dont have any experiance with this product in particular but I do know that Delrin is a great material for high wear situations as it actually becomes more slick as it wears. We used them in paintball gun bolts and my dad said they used it on railroad car couplers back in his day too.

754 · « **Reply #7 on:** December 24, 2011, 10:19:11 PM »

I THINK PHENOLIC MAY BE STIFFER than Delrin.. dont think a thin wall of Delrin is ideal.
Piston should NOT move in the seal during braking, once adjusted, the seal and piston as one move to perforn the braking in a sideways motion, then the seal puls it all back..

grcamna2 · « **Reply #8 on:** December 25, 2011, 05:51:36 AM »

I wonder how the Delrin will stand up to the intense heat of extended time of braking,such as riding down a steep mountain pass road with a fully loaded cycle?; doesn't Delrin have a limit as to how much heat that they can take.I plan on using my brakes extra hard and just want to be sure that I won't warp or melt the Delrin plastic caliper piston...aside from that I think it looks like an excellent material to use...does anybody have any ideas on this to help put me at ease ? I really like the idea of this material for a caliper piston,especially since it won't ever rust up like the O.E. steel piston does.

MoMo · « **Reply #9 on:** December 25, 2011, 08:45:13 AM »

Quote from: grcamna2 on December 25, 2011, 05:51:36 AM

I wonder how the Delrin will stand up to the intense heat of extended time of braking,such as riding down a steep mountain pass road with a fully loaded cycle?; doesn't Delrin have a limit as to how much heat that they can take.I plan on using my brakes extra hard and just want to be sure that I won't warp or melt the Delrin plastic caliper piston...aside from that I think it looks like an excellent material to use...does anybody have any ideas on this to help put me at ease ? I really like the idea of this material for a caliper piston,especially since it won't ever rust up like the O.E. steel piston does.

The units Kevin sells are made from either a Lincoln or Cadillac piston(not sure which but it is one of those), if the stuff works on a multi ton vehicle it should be fine on a 400 lb. Honda. I use nothing but his phenolic pistons and can say they are excellent. Any luck with a titled bike yet?...Larry

Psychonaut · « **Reply #10 on:** December 25, 2011, 08:58:38 AM »

Quote from: grcamna2 on December 25, 2011, 05:51:36 AM

I wonder how the Delrin will stand up to the intense heat of extended time of braking,such as riding down a steep mountain pass road with a fully loaded cycle?; doesn't Delrin have a limit as to how much heat that they can take.I plan on using my brakes extra hard and just want to be sure that I won't warp or melt the Delrin plastic caliper piston...aside from that I think it looks like an excellent material to use...does anybody have any ideas on this to help put me at ease ? I really like the idea of this material for a caliper piston,especially since it won't ever rust up like the O.E. steel piston does.

I don't know the working temp for delrin but I think the fluid will boil before the heat effects the delrin. Running pads that are very thin will transfer a lot of heat to the piston and then fluid too, this will boil fluid on a track car but not sure about a bike. Neither would be a concern on street applications for me though.

TwoTired · « **Reply #11 on:** December 25, 2011, 11:15:46 AM »

Where is this source of delrin brake pistons?

About Delrin:
http://en.wikipedia.org/wiki/Polyoxymethylene

I've heard of delirin brake pistons used in air brake systems, as it has good self lubricating properties, but not in glycol based hydraulics. The material doesn't seem a good fit for a replacement in the SOHC4 caliper design.

Why discount the readily available and tested phenolic ones mentioned here?

grcamna2 · « **Reply #12 on:** December 25, 2011, 11:26:20 AM »

Who has the phenolic caliper for sale ? I'd like to know of that source for my caliper so when I'm ready I can purchase it.

crazypj · « **Reply #13 on:** December 25, 2011, 11:39:09 AM »

The GM pistons are about $27.00 before you start machining them.
Pretty sure Delrin will be a bad idea as it's too flexible

754 · « **Reply #14 on:** December 25, 2011, 11:39:46 AM »

I could be wrong, on this next part about wall thickness....
but first, my first thought on the Delrin is it may be SQWOOGEY.. meaning it bends or deforms easy in thin section. Many plastics do I machined some dof forks this month, had a nasty workpiece shifting that could have got fugly.. as it was I nearly broke my thumb a almost tore a gash in my stomach.

Back to the piston, I think thin wall is preferable for several reasons, weight and heat transfer (to the fluid)..in this case I would not want the delrin. IZ think stainless is pretty doable to anyone that has access to a lathe and the time..

Anyone know the wall thickness of the phenolic.. where the outer edge contacts the pad or the shperical spacer ?

Ringo · « **Reply #15 on:** December 25, 2011, 04:38:02 PM »

I don't recall exactly, 754, but I want to say about 3/8" on that wall thickness...

TwoTired · « **Reply #16 on:** December 25, 2011, 05:18:20 PM »

Quote from: grcamna2 on December 25, 2011, 11:26:20 AM

Who has the phenolic caliper for sale ? I'd like to know of that source for my caliper so when I'm ready I can purchase it.

Send a PM to Kevin400F
http://forums.sohc4.net/index.php?topic=37883.msg391024#msg391024

Cheers,

grcamna2 · « **Reply #17 on:** December 25, 2011, 05:28:04 PM »

Thanks TT and Merry Christmas.

crazypj · « **Reply #18 on:** December 26, 2011, 12:43:48 AM »

I think OP got name wrong and it isn't Delrin but Phenolic
They were stock on a lot of newer Honda's from mid~late 80's on. (I've seen them a lot on off road bikes)
Don't transfer heat very well and don't corrode at all

faux fiddy · « **Reply #19 on:** December 26, 2011, 01:46:48 AM »

Delrin is great for replacing things like suspension bushings and any other mushy rubber parts, no doubt. it machines well, and hard as any plastic or rubber part, better and more than anything rubber.

Phenolic must be about equivalent, not sure why it wouldn't work for street use caiper pistons.

crazypj · « **Reply #20 on:** December 26, 2011, 07:58:42 AM »

Phenolic is much more rigid than Delrin.
If you hit Delrin with a hammer, it dents, if you hit Phenolic , it shatters
I haven't machined plastics for at least 37 yrs but from what I remember one is a thermoplastic and the other a thermo-setting plastic and cannot be re-formed by heat.
Bakelite was trade/generic name, for phenolic's, used since at least 1930's

grcamna2 · « **Reply #21 on:** December 26, 2011, 08:01:49 AM »

Thanks crazypj...that helps;I'm going to get a phenolic.

meerkat · « **Reply #22 on:** December 26, 2011, 10:35:57 AM »

Quote from: TwoTired on December 25, 2011, 05:18:20 PM

Quote from: grcamna2 on December 25, 2011, 11:26:20 AM
Who has the phenolic caliper for sale ? I'd like to know of that source for my caliper so when I'm ready I can purchase it.
Send a PM to Kevin400F
http://forums.sohc4.net/index.php?topic=37883.msg391024#msg391024
Cheers,

I bought one off Kevin and I'm very pleased with every aspect of it. Function, price and service.

grcamna2 · « **Reply #23 on:** December 26, 2011, 10:47:31 AM »

Thanks for the helpful feedback Meercat...; have you considered having a meercat for a pet? be a job to tame him I'm sure.

meerkat · « **Reply #24 on:** December 26, 2011, 01:31:39 PM »

Quote from: grcamna2 on December 26, 2011, 10:47:31 AM

Thanks for the helpful feedback Meercat...; have you considered having a meercat for a pet? be a job to tame him I'm sure.

Thanks for your reply.
I took a shine to meercats when there was a series of tv programmes about them.
Like most motorcyclists they seem to have a good sociable attitude and help each other.

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Author Topic: CB400F caliper piston made from Delrin:is it a good product ? (Read 6842 times)

Ringo

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