John;
On the coupe there is a puppet or relay valve (Honda uses both terms) that manages the vacuum diaphragm on the booster. Some times with age these seals will flatten out and not hold pressure. I have put small O rings under the lip of these two seals to keep them pressed against the cylinder. The piston on the shaft will wear through the chrome (showing copper) and allow fluid to bypass or go under the seal. So a rebuild should include replating the chrome on the piston to bring it back to size. And because the booster is a remote application it has a ball valve at the end of the piston with a rod that presses against the end of the piston housing or casting and releases the fluid pressure. If this rod is missing or is sticking it too could be causing your system to not release or release slowly. (see chapter 11a of the Coupe supplement shop manual)
You said you are using Dot 5 brake fluid.
If you press the peddle to quickly the master cylinder pistons can cause cavitations or small bubbles in the fluid. Go back to the Master cylinder and rebleed the master cylinder by having some one press the peddle just as you open the bleeder valve. Bleed the rear first then the front brake section if the master cylinder. I am sure you will find more air. Then rebleed the rear wheels and then the left front and right front calipers. Using someone in the car pumping (very slowly several times to keep from cavitating the master cylinder) and you will find more air in they system. If the system feels stronger and then seems to lose height in the peddle again, go back to the master cylinder and bleed it again as before.
I hope this helps.
Bill
> -----Original Message-----
> From:
> anzhonda600owners@yahoogroups.com
> [mailto:anzhonda600owners@yahoogroups.com]
> On Behalf Of
> brad
> fenn
> Sent:
> Sunday, September 23, 2012 9:11 PM
> To:
> anzhonda600owners@yahoogroups.com
> Subject:
> Re: [anzhonda600owners]
> Re: dragging front brakes?
> I would
> like to mention one thing, if you haven't replaced them I would double check > the front brake hoses. I have seen many on different types of cars where the > brake hoses actually swell shut where fluid will pass through them under > pressure,but won't return easily causing calipers to drag. Make sure you can > actually blow through them with ease. It is a fairly common problem on older > cars.
> From:
> John
>
> To:
> anzhonda600owners@yahoogroups.com
> Sent:
> Sun, September 23, 2012 10:36:47
> PM
> Subject:
> [anzhonda600owners] Re: dragging front
> brakes?
> Brake booster was pretty sticky but it is cleaned and reassembled and > calipers removed and all parts lubed well and reinstalled. system bled out > well, rear brakes adjusted and the brakes work pretty well but I think I need > some new cups in the booster to help out sealing it up as the ones in there > are 40 years old and a couple had some pitting and were a little hard. The > brakes release after about a second or so of using the pedal and it stops well > but you have to wait for about a left, right, left before going and its fine > but not great yet. I checked the check valve in the booster also it was also > good, so any other thoughts?
> --- In
> anzhonda600owners@yahoogroups.com
> ,
> "John" wrote:
> > Thanks again another easy
> check I may get lucky on one of these and not have a booster or master > issue.
> > --- In
> anzhonda600owners@yahoogroups.com
> ,
> brad fenn wrote:
> > > I will
> throw this out there. My first 600 I bought in 82 and it had been sitting
> > > for about 5 years. My front brakes were sticking on after > driving for a while.
> > > Checked calipers and hoses and found. no
> problems. If I cracked the bleeder it
> > > released the pressure and
> calipers released,so that pointed to master cylinders,
> > > Replaced
> both master cylinders and booster and problem was the same. It seemed I
> > > replaced everything I thought it could be. I finally checked the > vacuum check > > > valve in the vacuum hose and found it full of > corrosion. I cleaned vacuum check > > > valve and problem solved.
> Brakes worked fine ever since.
> > > I am
> a professional master mechanic and have been doing this for over 35 years
> > > and to this day can't understand how that fixed it, but it did.
> So like I said,
> > > just throwing that out there.. Brad
> > > From: jschmrbr
>
> > > To:
> anzhonda600owners@yahoogroups.com
> > Sent: Mon, September 17, 2012 6:20:55 PM
> > > Subject:
> [anzhonda600owners] Re: dragging front brakes?
> > > I have only had the car for about 6 weeks and prior it sat for > over 31 years. It > > > had the left flex line clogged and the rear > also clogged but we romoved the > > > cloggs and cleaned and flushed > the system before putting on a rebuilt master and > > > rebuilding the > rear wheel cylinders and calipers. All other brake parts were
> like new as this little car was not even broke in when parked. The underside > of > > > the vehicle and engine is cleaner then most 10 year old > vehicles on road > > > currently so we believe the odometer is correct > when we got it reading 3800! I > > > may not get another chance to > work on it till the weekend, at that point I will > > > try the > booster bypass too and see what happens.
> > > Thanks againto
> all
> > > John
> > > --- In
> anzhonda600owners@yahoogroups.com
> ,
> "William Colford"
> > > wrote:
> > > > John said it is he front calipers that are dragging.
> The brake system on
> > > > the Honda 600 is a split system and if
> the front part of the system is not
> > > > letting go that means
> the fluid is not going out of the front wheel
> > > > calipers.
> Which could be the bleed back hole on the master if it is both
> > front wheels. If it is one, then it is that wheel caliper. Bleed it > and > > > > see if the crud comes out. If not then you will have to > pull it apart and > > > > clean it. I have had that happen to a > single wheel caliper before using Dot > > > > 5.
> > > > Bill
> > > > From:
> anzhonda600owners@yahoogroups.com
> > > [mailto:
> anzhonda600owners@yahoogroups.com
> ]
> On Behalf Of drac
> > > > Sent: Monday, September 17, 2012 9:32
> AM
> > > > To:
> anzhonda600owners@yahoogroups.com
> > > Subject: [anzhonda600owners] Re: dragging front brakes?
> > > > check your return springs on your drums, i've had that > problem on other cars > > > > in the past. it could also be a leak > somewhere as well