Assorted brake system questions (REVCON)

D

dave silva

New member
Oct 2, 2009
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According to Revcon owners the stock brake system does a fine job of stopping the coach.

Other than the MC and the rear brake shoes, it uses all Toro parts, including the proportioning valve.

Does the GMC use the same one?

The Master cylinder is an orphan, hard to source and expensive. i think mine may be bad. I'm considering either GMC or P30 MC.

Maybe an adjustable proportioning valve?

I know people are reluctant to give advice on re-engineering brakes.

My thinking is that if i install parts made to stop a similarly sized vehicle, and if it works on a test drive then there is no reason not to trust
the result long term. Any flaw in that logic?

thanks
--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
The GMC nor the Toro did not use a proportioning valve. It is called a combination valve and it’s main purpose is to shut of either the front or the rear in the case of a leak so that you still have some braking. It also puts a small amount of pressure to the rears slightly before the fronts but not enough to be called proportional braking.

Emery Stora
77 Kingsley
Frederick, CO

>
> According to Revcon owners the stock brake system does a fine job of stopping the coach.
>
> Other than the MC and the rear brake shoes, it uses all Toro parts, including the proportioning valve.
>
> Does the GMC use the same one?
>
> The Master cylinder is an orphan, hard to source and expensive. i think mine may be bad. I'm considering either GMC or P30 MC.
>
> Maybe an adjustable proportioning valve?
>
> I know people are reluctant to give advice on re-engineering brakes.
>
> My thinking is that if i install parts made to stop a similarly sized vehicle, and if it works on a test drive then there is no reason not to trust
> the result long term. Any flaw in that logic?
>
> thanks
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> The GMC nor the Toro did not use a proportioning valve. It is called a combination valve and it's main purpose is to shut of either the front or
> the rear in the case of a leak so that you still have some braking. It also puts a small amount of pressure to the rears slightly before the fronts
> but not enough to be called proportional braking.

Thanks. So is the Toronado part compatible with the GMC?

--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
Yes it’s the same. Look for a 1976

Emery

>

>> The GMC nor the Toro did not use a proportioning valve. It is called a combination valve and it's main purpose is to shut of either the front or
>> the rear in the case of a leak so that you still have some braking. It also puts a small amount of pressure to the rears slightly before the fronts
>> but not enough to be called proportional braking.
>
> Thanks. So is the Toronado part compatible with the GMC?
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Kind of a word of caution applies here, and not only to brake system
replacement parts. The parts of today, are not even close to the
replacement parts of yesterday. Made in USA Wagner Lockheed or Bendix parts
no longer exist. Offshore suppliers abound, and the quality control is
sketchy at best and downright unsafe at the worst. BUYER BEWARE.
Jim Hupy

On Sun, May 12, 2019, 8:46 AM Emery Stora via Gmclist <

> Yes it’s the same. Look for a 1976
>
>
>
> Emery
>
> > On May 12, 2019, at 9:28 AM, dave silva via Gmclist <

> >

> >> The GMC nor the Toro did not use a proportioning valve. It is called a
> combination valve and it's main purpose is to shut of either the front or
> >> the rear in the case of a leak so that you still have some braking. It
> also puts a small amount of pressure to the rears slightly before the fronts
> >> but not enough to be called proportional braking.
> >
> > Thanks. So is the Toronado part compatible with the GMC?
> >
> > --
> > Dave & Ellen Silva
> >
> > 1972 Revcon Olds 455, toro drive train. All Stock
> >
> >
> >
> > _______________________________________________
> > 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
>
 
Doesn't Jim K or somebody else sell a NEW brass combination valve?

D C "Mac" Macdonald​
Amateur Radio - K2GKK​
k2gkk @ hotmail dot com​
USAF and FAA, Retired​
Oklahoma City, OK​
"The Money Pit"

________________________________
From: Gmclist on behalf of James Hupy via Gmclist
Sent: Sunday, May 12, 2019 10:59
To: gmclist
Cc: James Hupy
Subject: Re: [GMCnet] Assorted brake system questions (REVCON)

Kind of a word of caution applies here, and not only to brake system
replacement parts. The parts of today, are not even close to the
replacement parts of yesterday. Made in USA Wagner Lockheed or Bendix parts
no longer exist. Offshore suppliers abound, and the quality control is
sketchy at best and downright unsafe at the worst. BUYER BEWARE.
Jim Hupy

On Sun, May 12, 2019, 8:46 AM Emery Stora via Gmclist <

> Yes it’s the same. Look for a 1976
>
>
>
> Emery
>
> > On May 12, 2019, at 9:28 AM, dave silva via Gmclist <

> >

> >> The GMC nor the Toro did not use a proportioning valve. It is called a
> combination valve and it's main purpose is to shut of either the front or
> >> the rear in the case of a leak so that you still have some braking. It
> also puts a small amount of pressure to the rears slightly before the fronts
> >> but not enough to be called proportional braking.
> >
> > Thanks. So is the Toronado part compatible with the GMC?
> >
> > --
> > Dave & Ellen Silva
> >
> > 1972 Revcon Olds 455, toro drive train. All Stock
> >
> >
> >
> > _______________________________________________
> > 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
 
It's best to stay clear of the P30 for numerous reasons, fit, construction and pressure differences to name a few.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
> It's best to stay clear of the P30 for numerous reasons, fit, construction and pressure differences to name a few.
> Hal

I can probably deal with "fit' fairly well. Revcon turned the linkage 90 degrees so the MC is mounted left to right under the hood. It would be
fairly easy to mount any MC or move it to accommodate length.

What's the deal with P30 stuff or some other GM vehicle in the 10,000 lb range?

--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
The P30 has a larger piston and requires a higher pedal effort to achieve
the same pressure in the calipers and slave cylinders. There are other
differences, too, but that is enough for me. GMCs already have high enough
pedal effort.

Rick “not giving up pedal effort for a larger reservoir” Denney

On Sun, May 12, 2019 at 1:27 PM dave silva via Gmclist <

> > It's best to stay clear of the P30 for numerous reasons, fit,
> construction and pressure differences to name a few.
> > Hal
>
> I can probably deal with "fit' fairly well. Revcon turned the linkage 90
> degrees so the MC is mounted left to right under the hood. It would be
> fairly easy to mount any MC or move it to accommodate length.
>
> What's the deal with P30 stuff or some other GM vehicle in the 10,000 lb
> range?
>
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
 
If you have not replaced the origional valve, you should do so as the
origional was steel and corrosion has damaged them.

On Sun, May 12, 2019 at 10:37 AM James Hupy via Gmclist <

> Kind of a word of caution applies here, and not only to brake system
> replacement parts. The parts of today, are not even close to the
> replacement parts of yesterday. Made in USA Wagner Lockheed or Bendix parts
> no longer exist. Offshore suppliers abound, and the quality control is
> sketchy at best and downright unsafe at the worst. BUYER BEWARE.
> Jim Hupy
>
> On Sun, May 12, 2019, 8:46 AM Emery Stora via Gmclist <

>
> > Yes it’s the same. Look for a 1976
> >
> >
> >
> > Emery
> >
> > > On May 12, 2019, at 9:28 AM, dave silva via Gmclist <

> > >

> > >> The GMC nor the Toro did not use a proportioning valve. It is called a
> > combination valve and it's main purpose is to shut of either the front or
> > >> the rear in the case of a leak so that you still have some braking. It
> > also puts a small amount of pressure to the rears slightly before the
> fronts
> > >> but not enough to be called proportional braking.
> > >
> > > Thanks. So is the Toronado part compatible with the GMC?
> > >
> > > --
> > > Dave & Ellen Silva
> > >
> > > 1972 Revcon Olds 455, toro drive train. All Stock
> > >
> > >
> > >
> > > _______________________________________________
> > > 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
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> It's best to stay clear of the P30 for numerous reasons, fit, construction and pressure differences to name a few.
> Hal

I can probably deal with "fit' fairly well. Revcon turned the linkage 90 degrees so the MC is mounted left to right under the hood. It would be
fairly easy to mount any MC or move it to accommodate length.

What's the deal with P30 stuff or some other GM vehicle in the 10,000 lb range?

The P30 used poppet (sp?) valves for the fluid to drop from the reservoir to the cylinder. These valves have a tendency to get cocked and mess with
flow. They also use o rings instead of the more traditional cup seals. The master cylinder can also leak between the reservoir and cylinder assembly-I
have personally had two such failures. And the already stated loss of pressure because of the larger piston further aggravates the situation.
If you get a chance to look at the cutaway P30 that Wally Anderson made for Dave Lenzi you'll get the picture in a hurry.
Of course it's your choice but I won't be using a P30 again.
Hal


--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
My experience is similar to Hal's. I will not install any more of them.
There is a way to increase the reservoir capacity by using a remote
reservoir and a different top cover on the stock master cylinder.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Sun, May 12, 2019, 3:23 PM Hal StClair via Gmclist <

>
>

> on Sun, 12 May 2019 11:45
> > It's best to stay clear of the P30 for numerous reasons, fit,
> construction and pressure differences to name a few.
> > Hal
>
> I can probably deal with "fit' fairly well. Revcon turned the linkage 90
> degrees so the MC is mounted left to right under the hood. It would be
> fairly easy to mount any MC or move it to accommodate length.
>
> What's the deal with P30 stuff or some other GM vehicle in the 10,000 lb
> range?
>
> The P30 used poppet (sp?) valves for the fluid to drop from the reservoir
> to the cylinder. These valves have a tendency to get cocked and mess with
> flow. They also use o rings instead of the more traditional cup seals. The
> master cylinder can also leak between the reservoir and cylinder assembly-I
> have personally had two such failures. And the already stated loss of
> pressure because of the larger piston further aggravates the situation.
> If you get a chance to look at the cutaway P30 that Wally Anderson made
> for Dave Lenzi you'll get the picture in a hurry.
> Of course it's your choice but I won't be using a P30 again.
> Hal
>
>
> --
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
> 1975 Eleganza II, 101230,
>
> 1974 Eagle Bus 45',w/slideout,
>
> Rio Rancho, NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Are we talking Revcon or GMC here? All the Revcons I've seen (2 or 3) had duallies in the back... a very different braking setup from the GMC. As to
the right angle master cylinder, I bought a bread truck about ten years ago to make a remote vehicle. It had a 'right angle' master cylinder which
would probably work on any right angle mount. I forget quite who built it, one of the Indiana chassis upfitters. Who wouldn't sell me a passenger
seat pedestal, I had to have one fabbed locally. I bought the thing off Nalley Motor Truck Company in Atlanta, so it should of had a GM chassis,
likely a p30 or near.

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
 
That right angle master cylinder mount was used by Chrysler on Dodge and
Plymouth Van's and van conversions. I have also seen them used on Tvavco
motor homes of the same era. They used Dodge chassis in those years. Looks
like they might work on a GMC if it weren't for the wiper motor being there.
Never tried one there though.
Jim Hupy

On Tue, May 14, 2019, 5:53 AM Johnny Bridges via Gmclist <

> Are we talking Revcon or GMC here? All the Revcons I've seen (2 or 3) had
> duallies in the back... a very different braking setup from the GMC. As to
> the right angle master cylinder, I bought a bread truck about ten years
> ago to make a remote vehicle. It had a 'right angle' master cylinder which
> would probably work on any right angle mount. I forget quite who built
> it, one of the Indiana chassis upfitters. Who wouldn't sell me a passenger
> seat pedestal, I had to have one fabbed locally. I bought the thing off
> Nalley Motor Truck Company in Atlanta, so it should of had a GM chassis,
> likely a p30 or near.
>
> 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
>
 
> Are we talking Revcon or GMC here? All the Revcons I've seen (2 or 3) had duallies in the back... a very different braking setup from the GMC.
> As to the right angle master cylinder, I bought a bread truck about ten years ago to make a remote vehicle. It had a 'right angle' master cylinder
> which would probably work on any right angle mount. I forget quite who built it, one of the Indiana chassis upfitters. Who wouldn't sell me a
> passenger seat pedestal, I had to have one fabbed locally. I bought the thing off Nalley Motor Truck Company in Atlanta, so it should of had a GM
> chassis, likely a p30 or near.
>
> johnny

My revcon has one axle and single wheels in the back. Later models had two axles and four wheels in the back. None of them came with duallies until a
few years ago when a new company used the name on a ford powered offroad class C.

--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
OK, singles. Still a very diffe3rent braking setup. Only6 the front of the rears is driven, no? And the rear is a tag?

--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
 
> OK, singles. Still a very different braking setup. Only the front of the rears is driven, no? And the rear is a tag?
>
> --johnny

No, it's FWD, Like a GMC but all original Tornado.

The brake system is almost all Toro. Rear drums are a bit bigger, fornt disks are the same. MC is unknown.

--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
Same suspension, or sprung axles?

--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
 
> Same suspension, or sprung axles?
>
> --johnny

The revcon uses a drop axle on leave springs in the back with 12" drum brakes.

--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock
 
Then its rear brakes will behave very differently from the GMC rear brakes.

--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
 
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