Randy, how far West are you coming? If you get as far as Oregon, be sure to
give Judy and I a call. Would love to see you and Margie.
Jim Hupy
Salem, Oregon
> > > Quote:
> > > > Randy said...." this MC works better than the OEM MC I was using
> previously. I had plenty of stopping power before but now I have reduced
> > > > my stopping distance significantly."
> > > >
> > > > Then you said.... "It left me confused about which MC you are using
> now and what kind of braking you have, and what has reduced stopping
> > > > power."
> > >
> > > So, Randy now has reduced stopping distance, therefore more stopping
> power, so nothing has reduced stopping power. Au contraire.
> > >
> > > I think he's using the 1-1/8" with
> > >
> > > I have the Dave Lenzi two-port booster; I assume it's metric but I'll
> have to check; I didn't have to send a core. I understood that you have
> > > the same and have fitted the 1-1/4" MC. I'm asking if
> > > 1. You can share the length of the pushrod to save me some time if I
> go that way as well.
> > > 2. You think the 1-1/8" MC can use a pushrod of the same length. (I
> think you answered that they look the same but haven't installed to be
> > > sure.)
> > >
> > > It seems like there's three options...
> > > NAPA NMC M2580 ......44mm, 1-1/4" bore for metric
> > > Cardone 13-1870......44mm, 1-1/8" bore for OEM
> > > NAPA NMC M2580 ......44mm, 1-1/4" bore for metric
> > >
> > > Did I get that right?
> >
> > You're first an third options are the same did you intend that? And the
> step bore on them is 40mm, not the 44mm that you state.
> >
> > One more option is of coarse the OEM MC which does not have the 40mm
> step bore.
> >
> > Still not sure what Randy is using. Would have to confirm that with him.
> >
> > To get the pushrod length, I'd have to go out in the snowdrift and
> remove the MC. I will be traveling to Florida between Christmas and New
> Years.
> > Should be there by 1st or second week of January. Can you wait until
> then?
> >
> > I think there is a high probability that the pushrod length would be the
> same between the 40mm, 1-1/8" bore MC, and the 40mm, 1-1/4" bore. But
> > would highly advise doing the adjustment procedure on both and measuring
> the two to verify. The last thing you want is for the MC piston to not
> > retract all of the way holding the brakes on. JMHO
>
> I apologize if I misled anyone. I'm not at home (headed to the west and
> currently somewhere in Texas) so cannot verify for sure which master
> cylinder
> (thanks to Jim H for reminding me not to use acronyms) that I am using. I
> now believe it is a Cardone 13-2058 which I believe crosses to the Napa
> M2609 that Larry mentioned as having the 1 1/8" bore. The seat into the
> Master Cylinder fits the original booster. I was concerned with the volume
> with the 1 1/8" bore but it seems to give me a good pedal That may be the
> reason that I now have better stopping distance. I was originally using
> the GMC Motorhome OEM Master Cylinder that has a 1 1/4" bore. The new
> Master Cylinder that I'm using has the 40mm step bore which probably
> eliminates
> concern for volume. Here is a link to a Cardone Chart that gives the bore
> sizes (including the step bore) for all of the master cylinders they make.
>
http://www.pbwdist.com/catalogs/Cardon_MasterCylinders_IDGuide_2013.pdf
>
> I have not measured pressures at the caliphers so do not know if I have
> increased clamping power (I suspect I do). Also, I have not verified if the
> combination valve I have limits psi to what was originally the rears.
>
> I used the original push rod that I had in the OEM Master Cylinder. I
> have had a bit of drop in mpg after putting the Master Cylinder on and have
> not
> found a cause for that yet. My theory is that I may have the push rod
> just a bit too long maintaining some drag on the pads. Also, I wonder that
> because these Master Cylinders are for disc/drum combinations if there is
> a residual check valve causing some pressure to remain on the calipher like
> those valves did for drum brakes. If any of these things existed I would
> think I would have a lot higher temps on the rotors. I have been measuring
> those temps and haven't notice temps high enough to be of concern. Funny,
> though, the front rear rotors run about 20 degrees hotter than the rear
> rear or the fronts. Anyway, I don't believe I have sorted all the issues
> but am happy with the braking.
>
> --
> Randy & Margie
> '77 Eleganza II '403'
> Battlefield, MO
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>