Brakes

[johnny]

Starting in redoing the brake hydraulic system, which isn't working well. I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM had a
bigger piston diameter (giving greater pressure to the pads) uses the stock disc or does this mean the disc has to swap as well? I realize the 80MM
is going to need some massaging with my grinder to clear. I hafta choose before I go for new hoses.

--johnny

--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell

 

[john r. lebetski]

The down side is it requires more volume to operate. Also check that the bleeder will be at 12 noon as installed. Otherwise you need to remove to
rotate clocking to bleed. I'm stock, so just going of issues I have "heard of".
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[6cuda6]

From what ive read and dont quote me on this, it just the caliper and hoses that qet replaced giving you a bigger piston caliper.

The upside....better clamping power....downside more fluid volume so you either upgrade your master cylinder to something with a bigger reservoir or
youll have to be very deligent in checking fluid level.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[adolph santorine]

If you upgrade just the fronts, you can still use the preferred stock master cylinder.

It’s when you start messing with the intermediate and rear brakes that things get interesting.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> From what ive read and dont quote me on this, it just the caliper and hoses that qet replaced giving you a bigger piston caliper.
>
> The upside....better clamping power....downside more fluid volume so you either upgrade your master cylinder to something with a bigger reservoir or
> youll have to be very deligent in checking fluid level.
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Ken H.]

Johnny,

If you Google "GMCNet Archive" and then search for "80 mm calipers" you'll
get the last few years of related 'net traffic. Here's the most essential
information:
https://groups.google.com/forum/#!searchin/gmcnet-archive/80$20mm$20calipers%7Csort:date/gmcnet-archive/0IV4h8Yv1FI/iFJ0mULyAAAJ

As far as MC -- with everything else OEM, the MC will handle the 80mm OK.
There's one little bump on the outside of the 80 mm casting which can be
cut off very easily to clear the Alcoas. The OEM pads fit the 80 mm (I
strongly recommend Performance Friction 0052.20's).

Ken H.

On Sat, Nov 2, 2019 at 9:36 AM Johnny Bridges via Gmclist <

> Starting in redoing the brake hydraulic system, which isn't working well.
> I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM had a
> bigger piston diameter (giving greater pressure to the pads) uses the
> stock disc or does this mean the disc has to swap as well? I realize the
> 80MM
> is going to need some massaging with my grinder to clear. I hafta choose
> before I go for new hoses.
>
> --johnny
>
>
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me
> in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[adolph santorine]

In the link sent by Ken, the Autozone reman calipers are mentioned.

Check them before you leave the store. The cores get thrown into a crate during the process, and the holes on the ears for the bolts can be oblong. As in less than round. As in the bolt won’t go in there. You get it.

The last thing you want to be doing with that casting is trying to bend (break?) them back out to put it all together.

I learned that the hard way.

BTW, I usually go to the “Red” Store (Advance), but since Dave Lenzi recommended that I use the AutoZone calipers, I used the Orange store.

They are a better rebuild.

Just say’in.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> Johnny,
>
> If you Google "GMCNet Archive" and then search for "80 mm calipers" you'll
> get the last few years of related 'net traffic. Here's the most essential
> information:
> https://groups.google.com/forum/#!searchin/gmcnet-archive/80$20mm$20calipers%7Csort:date/gmcnet-archive/0IV4h8Yv1FI/iFJ0mULyAAAJ
>
> As far as MC -- with everything else OEM, the MC will handle the 80mm OK.
> There's one little bump on the outside of the 80 mm casting which can be
> cut off very easily to clear the Alcoas. The OEM pads fit the 80 mm (I
> strongly recommend Performance Friction 0052.20's).
>
> Ken H.
>
> On Sat, Nov 2, 2019 at 9:36 AM Johnny Bridges via Gmclist <

>
>> Starting in redoing the brake hydraulic system, which isn't working well.
>> I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM had a
>> bigger piston diameter (giving greater pressure to the pads) uses the
>> stock disc or does this mean the disc has to swap as well? I realize the
>> 80MM
>> is going to need some massaging with my grinder to clear. I hafta choose
>> before I go for new hoses.
>>
>> --johnny
>>
>>
>> --
>> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
>> Braselton, Ga.
>> I forgive them all, save those who hurt the dogs. They must answer to me
>> in hell
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Jim Hupy]

Ponder this. 100 psi line pressure applied to a caliper piston that has an
area of 2 square inches, versus 100 psi line pressure applied to a caliper
piston of 4 square inches.
Question? Which one has more stopping pressure? (Grin)
Jim Hupy
Salem, Oregon

On Sat, Nov 2, 2019, 8:52 AM Dolph Santorine via Gmclist <

> In the link sent by Ken, the Autozone reman calipers are mentioned.
>
> Check them before you leave the store. The cores get thrown into a crate
> during the process, and the holes on the ears for the bolts can be oblong.
> As in less than round. As in the bolt won’t go in there. You get it.
>
> The last thing you want to be doing with that casting is trying to bend
> (break?) them back out to put it all together.
>
> I learned that the hard way.
>
> BTW, I usually go to the “Red” Store (Advance), but since Dave Lenzi
> recommended that I use the AutoZone calipers, I used the Orange store.
>
> They are a better rebuild.
>
> Just say’in.
>
>
> Dolph
>
> DE AD0LF
>
> Wheeling, West Virginia
>
> 1977 26’ ex-PalmBeach
> Howell EFI & EBL, Reaction Arms, Manny Transmission
>
> “The Aluminum and Fiberglass Mistress"
>
> > On Nov 2, 2019, at 11:39 AM, Ken Henderson via Gmclist <

> >
> > Johnny,
> >
> > If you Google "GMCNet Archive" and then search for "80 mm calipers"
> you'll
> > get the last few years of related 'net traffic. Here's the most
> essential
> > information:
> >
> https://groups.google.com/forum/#!searchin/gmcnet-archive/80$20mm$20calipers%7Csort:date/gmcnet-archive/0IV4h8Yv1FI/iFJ0mULyAAAJ
> >
> > As far as MC -- with everything else OEM, the MC will handle the 80mm OK.
> > There's one little bump on the outside of the 80 mm casting which can be
> > cut off very easily to clear the Alcoas. The OEM pads fit the 80 mm (I
> > strongly recommend Performance Friction 0052.20's).
> >
> > Ken H.
> >
> > On Sat, Nov 2, 2019 at 9:36 AM Johnny Bridges via Gmclist <

> >
> >> Starting in redoing the brake hydraulic system, which isn't working
> well.
> >> I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM
> had a
> >> bigger piston diameter (giving greater pressure to the pads) uses the
> >> stock disc or does this mean the disc has to swap as well? I realize
> the
> >> 80MM
> >> is going to need some massaging with my grinder to clear. I hafta
> choose
> >> before I go for new hoses.
> >>
> >> --johnny
> >>
> >>
> >> --
> >> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> >> Braselton, Ga.
> >> I forgive them all, save those who hurt the dogs. They must answer to
> me
> >> in hell
> >>
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[adolph santorine]

P x A

Of course, I’m still hung up on measuring velocity in furlongs per fortnight.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> Ponder this. 100 psi line pressure applied to a caliper piston that has an
> area of 2 square inches, versus 100 psi line pressure applied to a caliper
> piston of 4 square inches.
> Question? Which one has more stopping pressure? (Grin)
> Jim Hupy
> Salem, Oregon
>
> On Sat, Nov 2, 2019, 8:52 AM Dolph Santorine via Gmclist <

>
>> In the link sent by Ken, the Autozone reman calipers are mentioned.
>>
>> Check them before you leave the store. The cores get thrown into a crate
>> during the process, and the holes on the ears for the bolts can be oblong.
>> As in less than round. As in the bolt won’t go in there. You get it.
>>
>> The last thing you want to be doing with that casting is trying to bend
>> (break?) them back out to put it all together.
>>
>> I learned that the hard way.
>>
>> BTW, I usually go to the “Red” Store (Advance), but since Dave Lenzi
>> recommended that I use the AutoZone calipers, I used the Orange store.
>>
>> They are a better rebuild.
>>
>> Just say’in.
>>
>>
>> Dolph
>>
>> DE AD0LF
>>
>> Wheeling, West Virginia
>>
>> 1977 26’ ex-PalmBeach
>> Howell EFI & EBL, Reaction Arms, Manny Transmission
>>
>> “The Aluminum and Fiberglass Mistress"
>>
>>> On Nov 2, 2019, at 11:39 AM, Ken Henderson via Gmclist <

>>>
>>> Johnny,
>>>
>>> If you Google "GMCNet Archive" and then search for "80 mm calipers"
>> you'll
>>> get the last few years of related 'net traffic. Here's the most
>> essential
>>> information:
>>>
>> https://groups.google.com/forum/#!searchin/gmcnet-archive/80$20mm$20calipers%7Csort:date/gmcnet-archive/0IV4h8Yv1FI/iFJ0mULyAAAJ
>>>
>>> As far as MC -- with everything else OEM, the MC will handle the 80mm OK.
>>> There's one little bump on the outside of the 80 mm casting which can be
>>> cut off very easily to clear the Alcoas. The OEM pads fit the 80 mm (I
>>> strongly recommend Performance Friction 0052.20's).
>>>
>>> Ken H.
>>>
>>> On Sat, Nov 2, 2019 at 9:36 AM Johnny Bridges via Gmclist <

>>>
>>>> Starting in redoing the brake hydraulic system, which isn't working
>> well.
>>>> I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM
>> had a
>>>> bigger piston diameter (giving greater pressure to the pads) uses the
>>>> stock disc or does this mean the disc has to swap as well? I realize
>> the
>>>> 80MM
>>>> is going to need some massaging with my grinder to clear. I hafta
>> choose
>>>> before I go for new hoses.
>>>>
>>>> --johnny
>>>>
>>>>
>>>> --
>>>> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
>>>> Braselton, Ga.
>>>> I forgive them all, save those who hurt the dogs. They must answer to
>> me
>>>> in hell
>>>>
>>>>
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[powwerjon]

If you haven’t already seen this photo album then this is the ‘How Too” by Arch.

http://www.gmcmotorhome.com/commodore/front_brake/index.html

JR Wright
Michigan

>
> P x A
>
> Of course, I’m still hung up on measuring velocity in furlongs per fortnight.
>
>
> Dolph
>
> DE AD0LF
>
> Wheeling, West Virginia
>
> 1977 26’ ex-PalmBeach
> Howell EFI & EBL, Reaction Arms, Manny Transmission
>
> “The Aluminum and Fiberglass Mistress"
>

>>
>> Ponder this. 100 psi line pressure applied to a caliper piston that has an
>> area of 2 square inches, versus 100 psi line pressure applied to a caliper
>> piston of 4 square inches.
>> Question? Which one has more stopping pressure? (Grin)
>> Jim Hupy
>> Salem, Oregon
>>
>> On Sat, Nov 2, 2019, 8:52 AM Dolph Santorine via Gmclist <

>>
>>> In the link sent by Ken, the Autozone reman calipers are mentioned.
>>>
>>> Check them before you leave the store. The cores get thrown into a crate
>>> during the process, and the holes on the ears for the bolts can be oblong.
>>> As in less than round. As in the bolt won’t go in there. You get it.
>>>
>>> The last thing you want to be doing with that casting is trying to bend
>>> (break?) them back out to put it all together.
>>>
>>> I learned that the hard way.
>>>
>>> BTW, I usually go to the “Red” Store (Advance), but since Dave Lenzi
>>> recommended that I use the AutoZone calipers, I used the Orange store.
>>>
>>> They are a better rebuild.
>>>
>>> Just say’in.
>>>
>>>
>>> Dolph
>>>
>>> DE AD0LF
>>>
>>> Wheeling, West Virginia
>>>
>>> 1977 26’ ex-PalmBeach
>>> Howell EFI & EBL, Reaction Arms, Manny Transmission
>>>
>>> “The Aluminum and Fiberglass Mistress"
>>>
>>>> On Nov 2, 2019, at 11:39 AM, Ken Henderson via Gmclist <

>>>>
>>>> Johnny,
>>>>
>>>> If you Google "GMCNet Archive" and then search for "80 mm calipers"
>>> you'll
>>>> get the last few years of related 'net traffic. Here's the most
>>> essential
>>>> information:
>>>>
>>> https://groups.google.com/forum/#!searchin/gmcnet-archive/80$20mm$20calipers%7Csort:date/gmcnet-archive/0IV4h8Yv1FI/iFJ0mULyAAAJ
>>>>
>>>> As far as MC -- with everything else OEM, the MC will handle the 80mm OK.
>>>> There's one little bump on the outside of the 80 mm casting which can be
>>>> cut off very easily to clear the Alcoas. The OEM pads fit the 80 mm (I
>>>> strongly recommend Performance Friction 0052.20's).
>>>>
>>>> Ken H.
>>>>
>>>> On Sat, Nov 2, 2019 at 9:36 AM Johnny Bridges via Gmclist <

>>>>
>>>>> Starting in redoing the brake hydraulic system, which isn't working
>>> well.
>>>>> I'm told 'Use the 80MM caliper'. Now, does this simply mean the 80MM
>>> had a
>>>>> bigger piston diameter (giving greater pressure to the pads) uses the
>>>>> stock disc or does this mean the disc has to swap as well? I realize
>>> the
>>>>> 80MM
>>>>> is going to need some massaging with my grinder to clear. I hafta
>>> choose
>>>>> before I go for new hoses.
>>>>>
>>>>> --johnny
>>>>>
>>>>>
>>>>> --
>>>>> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
>>>>> Braselton, Ga.
>>>>> I forgive them all, save those who hurt the dogs. They must answer to
>>> me
>>>>> in hell
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> GMCnet mailing list
>>>>> Unsubscribe or Change List Options:
>>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>>>
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[LQQKatJon]

Johnny- hope I am not too late on this post.

I was witness to 3 80mm brake installations from aug-late sept this year. The final one being on my coach. This seems to be a very common and
proven way to improve the brakes. I think 50% of the coaches that show up at our rally's are running 80mm front brake upgrade, running a stock master
cylinder.

We planned on doing the brakes on my friend's coach, so he went and bought 2x the parts for the 80mm upgrade, and handed me the parts to do my coach
as well in exchange for assisting him with doing his brakes. He cross referenced the parts on Bdub's site at autozone, and bought some there, and
some online. Interesting like mentioned above, we ended up with a-1 cardone remanfuactured calipers, and some were different. I have a different
bleeder screw size on my passenger vs my driver side. Annoying, but the calipers worked.

The other "upgrade" is we went with performance friction pads. My brakes and his brakes are significantly better stopping. Mine had new
calipers/pads 7 years ago. I cann't say if it is the performance friction pads, or the 80mm, but I noticed a significant brake improvement over my
stock setup. I am now braking almost always with a very light pedal push and it is stopping via- the booster power. I used to press down, and if
I had to stop any quicker, there was a stopping point and I had to use force. Unless I am panic stopping, it is now stopping what I would consider
like a normal car. I can still panic stop pretty hard, but I just have not even bothered to test or play with trying to stop that fast.

here are a few things observed and learned over 3 brake installs:

1. if you do use the perfomance friction pads. Proper breaking in of the pad to the rotors is a key item. We did not do a good job with coach
#1, and it took a while for improved braking after lots and lots of hard stops to get pads to bed in. With coach #2 and my coach, we used a
"grizzly grinder rotor conditioner" witch basically sands the rotors. (many will Dual action sand the rotors). with conditioning the rotors, the
perfomance friction pads bedded in almost immediately.

2. I did not notice in the write ups, but you need to file/grind the knuckle. in the arc, where the caliper sits, there is a ridge of casting seam
sticking up. That can rub on caliper.(was rubbing on coach). very small ridge, needs to be ground down. it might not be an issue(coach #2 was
driven a bit before it was brought to attention, and when we took it apart, it basically scratched the paint off the caliper- nothing more).

3. getting the brake hoses off is where most of the work/time installing came from. use lots of penetrating oil and soak-soak-soak.

4. we pretty much installed the caliper, then went after the hose, looking how it needed to be bent a little in the vice at the caliper. pretty
easy to figure out and do once you have he caliper mounted and know the hose routing. trying to think of how to do that bend with out the caliper
mounted, seems to be wasted energy and thinking. Look at carl S's photo album to see how to easily mount the hose bracket to the front of the
upper control arm.

5. I used the hupy bleeder and had no issues with bleeding the calipers.

I have heard mention some worry about running out of fluid in the stock master cylinder. That maybe? but I know there are many that do not have
that problem. The majority of our club run's the 80mm caplipers with stock master cylinder for years/many miles. I see it only as a possibility if
you plan on getting the last mile out of the pads. I doubt I will ever run a set of front pads on my GMC to even 50% wear. cheap and easy to keep
good pads in the GMC, vs having brake issues or worrying about chewing up a rotor.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/