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longhorn717 · 09-19-2010, 01:46 PM

Hey guys I've got that old 80 Honda CB400t I was on here talking about not too long ago and need some advice on the brake cylinder. I got a rebuild kit from oldbikebarn.com and it seems to be a very nice kit. only problem is the new "plunger" doesn't want to fit into the cylinder with the little rubber boot that is supposed to fit on it. The old one fits in so nice but unfortunately the rubber boot on that one isn't reuseable. any ideas to make it work right?

longhorn717 · 09-19-2010, 03:30 PM

Anyone? I really need to get back on the road.

seruzawa · 09-19-2010, 06:14 PM

They sent the wrong kit.

longhorn717 · 09-20-2010, 08:02 AM

Sorry strike one. I just checked with the people over at OldBikeBarn and I got the correct kit. I also checked the package against their website and the part number matches. So I'm still not sure what the issue is with this dang seal but I'm gonna go try to persuade it to fit again.

pushrod · 09-20-2010, 08:38 AM

If it's close, then you have the right part, and you need to carefully coax the plunger into the cylinder. Of course, keep a sheen of brake fluid on it to keep it slippery.

If it ain't close, see Seru's post.

seruzawa · 09-20-2010, 09:19 AM

If it doesn't fit and looks different than the old one then there is something wrong with the kit. Sometimes a wrong part number gets loaded onto a package or into a computer. If you order a lot of parts you will run into this occasionally.

I got a wrong piston for an IT175 just last spring and the shop had to get the supplier to find the right part. Turns out the boxes were mislabeled at the warehouse.

The_AirHawk · 09-20-2010, 10:13 AM

If appearance and size are substantially different = Wrong Part, regardless of what the package sez. I run-into this literally all the time, especially with seals.

longhorn717 · 09-20-2010, 12:52 PM

no no. this turns out to be the correct part. Got it all put back together again. problem was i had to wiggle it around alot. but once I figured out how to get it in there it would go up and down just fine. that snap ring though is a royal pain in the @$$. I've moved on down to the caliper and got the piston out. What was behind it though was not comforting. about a 1/4 of the space was filled with brown-orangish sludge. I ordered a caliper rebuild kit as well for this bike. but I went on what my manual told me and got one for a similar honda bike that it said had the same caliper. well none of the dang seals in that one are big enough for the caliper I have. This is really frustrating. I don't think this bike has had a brake overhaul since the thing was built in 1980.

pushrod · 09-20-2010, 01:27 PM

Unless you have another (new) puck, be very careful cleaning the old one! Don't use anything more aggressive than a toothbrush (a real toothbrush, not a shop one) and maybe some baking soda.

If you cut the surface ("profile") at all, it'll leak. So don't use sandpaper or even a metal brush.

To add to your fun, I'd recommend you put new hoses on it, too. The old ones are almost certainly shot.

Lastly (or firstly), cover your gas tank (and maybe even the front fender) with a layer of plastic (cut apart a couple grocery bags) and top that with an old bath towel. Even if the paint is already toast, you sure don't want to spill any brake fluid on it.

The_AirHawk · 09-20-2010, 01:28 PM

Quote:

Originally Posted by longhorn717

I don't think this bike has had a brake overhaul since the thing was built in 1980.

Few of them have.

It's wholly-unecessary to do so, if you bleed the brakes regularly. But then, most motos are treated like cars or appliances - expected to work, then ignored...... until they quit working......

09-19-2010, 01:46 PM	#1
longhorn717 Registered Member Join Date: Aug 2010 Location: hill country, tx Posts: 39	brake reservior overhaul Hey guys I've got that old 80 Honda CB400t I was on here talking about not too long ago and need some advice on the brake cylinder. I got a rebuild kit from oldbikebarn.com and it seems to be a very nice kit. only problem is the new "plunger" doesn't want to fit into the cylinder with the little rubber boot that is supposed to fit on it. The old one fits in so nice but unfortunately the rubber boot on that one isn't reuseable. any ideas to make it work right? __________________ Ride Hard, Ride Fast.

09-19-2010, 03:30 PM	#2
longhorn717 Registered Member Join Date: Aug 2010 Location: hill country, tx Posts: 39	Anyone? I really need to get back on the road. __________________ Ride Hard, Ride Fast.

09-19-2010, 06:14 PM	#3
seruzawa Robby Join Date: Nov 2001 Location: 8501 ft. Posts: 16,803	They sent the wrong kit. __________________ I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tanhauser Gate. All those moments will be lost in time, like tears in the rain.

09-20-2010, 08:02 AM	#4
longhorn717 Registered Member Join Date: Aug 2010 Location: hill country, tx Posts: 39	Sorry strike one. I just checked with the people over at OldBikeBarn and I got the correct kit. I also checked the package against their website and the part number matches. So I'm still not sure what the issue is with this dang seal but I'm gonna go try to persuade it to fit again. __________________ Ride Hard, Ride Fast.

09-20-2010, 08:38 AM	#5
pushrod Founding Member Join Date: Nov 2001 Location: Baja 'Bama Posts: 3,478	If it's close, then you have the right part, and you need to carefully coax the plunger into the cylinder. Of course, keep a sheen of brake fluid on it to keep it slippery. If it ain't close, see Seru's post. __________________ You would not understand, this is not how I am... I have become - Comfortably Numb.

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09-20-2010, 09:19 AM	#6
seruzawa Robby Join Date: Nov 2001 Location: 8501 ft. Posts: 16,803	If it doesn't fit and looks different than the old one then there is something wrong with the kit. Sometimes a wrong part number gets loaded onto a package or into a computer. If you order a lot of parts you will run into this occasionally. I got a wrong piston for an IT175 just last spring and the shop had to get the supplier to find the right part. Turns out the boxes were mislabeled at the warehouse. __________________ I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tanhauser Gate. All those moments will be lost in time, like tears in the rain.

09-20-2010, 10:13 AM	#7
The_AirHawk Founding Member Join Date: Jun 2007 Location: Livin' in a Van: down by the Mariana Trench Posts: 10,891	If appearance and size are substantially different = Wrong Part, regardless of what the package sez. I run-into this literally all the time, especially with seals. __________________ *Parfois, on fait pas semblant* Sometimes, it's not pretend Oderint Dum Metuant Let them hate so long as they fear политики предпочитают безоружных крестьян Politicians Prefer Unarmed Peasants Nothing to see here, Citizen. Move along now...

09-20-2010, 12:52 PM	#8
longhorn717 Registered Member Join Date: Aug 2010 Location: hill country, tx Posts: 39	no no. this turns out to be the correct part. Got it all put back together again. problem was i had to wiggle it around alot. but once I figured out how to get it in there it would go up and down just fine. that snap ring though is a royal pain in the @$$. I've moved on down to the caliper and got the piston out. What was behind it though was not comforting. about a 1/4 of the space was filled with brown-orangish sludge. I ordered a caliper rebuild kit as well for this bike. but I went on what my manual told me and got one for a similar honda bike that it said had the same caliper. well none of the dang seals in that one are big enough for the caliper I have. This is really frustrating. I don't think this bike has had a brake overhaul since the thing was built in 1980. __________________ Ride Hard, Ride Fast.

09-20-2010, 01:27 PM	#9
pushrod Founding Member Join Date: Nov 2001 Location: Baja 'Bama Posts: 3,478	Unless you have another (new) puck, be very careful cleaning the old one! Don't use anything more aggressive than a toothbrush (a real toothbrush, not a shop one) and maybe some baking soda. If you cut the surface ("profile") at all, it'll leak. So don't use sandpaper or even a metal brush. To add to your fun, I'd recommend you put new hoses on it, too. The old ones are almost certainly shot. Lastly (or firstly), cover your gas tank (and maybe even the front fender) with a layer of plastic (cut apart a couple grocery bags) and top that with an old bath towel. Even if the paint is already toast, you sure don't want to spill any brake fluid on it. __________________ You would not understand, this is not how I am... I have become - Comfortably Numb.