TravcoForum.com

Travco Classic Motorhome Support & Discussion Forum

Skip to content

Change font size

Board index » Maintenance » Brakes
Post here for Brake System related Discussion

Re: Travco 270 lost the Hydrovac brake booster

Unread postby 77Travco on Tue Sep 02, 2014 9:11 pm

My 77 has hydroboost so most of what you guys have been talking about is foreign to me, lol. I will try to take a few pics tomorrow and post them up.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1146
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: Travco 270 lost the Hydrovac brake booster

Unread postby RobC on Thu Sep 04, 2014 11:43 am

I will take a look today but yeah- pretty sure mine is hydroboost. I will grab some shots this afternoon and post them along with a few of my rig in its torn down state.

Rob
RobC
Senior Contributor
Senior Contributor
 
Posts: 239
Joined: Mon Jul 01, 2013 2:30 pm
Travco Model: 1976 270

Re: Travco 270 lost the Hydrovac brake booster

Unread postby Roadrash on Thu Sep 04, 2014 1:21 pm

I'm looking forward to seeing some pics of the hydroboost setup.
User avatar
Roadrash
Contributing Member
Contributing Member
 
Posts: 43
Joined: Sun Jan 27, 2013 10:46 pm
Location: North Vancouver, BC, Canada
Travco Model: 1974 270

Re: Travco 270 lost the Hydrovac brake booster

Unread postby Acesneights on Thu Sep 04, 2014 8:25 pm

77Travco wrote:My 77 has hydroboost so most of what you guys have been talking about is foreign to me, lol. I will try to take a few pics tomorrow and post them up.


http://dave78chieftain.zxq.net/HydroVac_brakes.html is a pretty good explanation of the Hydravac system.
1975 Travco 270
1974 Travco 220 Parts unit
User avatar
Acesneights
Site Admin
Site Admin
 
Posts: 1755
Joined: Tue Jan 22, 2013 7:01 am
Location: North East Ct
Travco Model: 1975 270,1974 220

Re: Travco 270 lost the Hydrovac brake booster

Unread postby 77Travco on Mon Sep 08, 2014 11:24 am

Sorry guys... I got completely side tracked this last weekend with other projects and forgot. I am at work today but will leave myself a reminder about this.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1146
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: Travco 270 lost the Hydrovac brake booster

Unread postby 77Travco on Tue Sep 09, 2014 1:39 pm

It's pretty dirty under there with surface rust and all but here is a pic. Next time I drive by a car wash I need to power spray that area.

Pretty simple setup really... A Hydroboost unit attached to a master cylinder that then has the front and rear lines going through a proportioning valve (mounted on the frame) on their way to the wheels.
You do not have the required permissions to view the files attached to this post.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1146
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: Travco 270 lost the Hydrovac brake booster

Unread postby Acesneights on Tue Sep 09, 2014 7:02 pm

Way better setup IMHO.
1975 Travco 270
1974 Travco 220 Parts unit
User avatar
Acesneights
Site Admin
Site Admin
 
Posts: 1755
Joined: Tue Jan 22, 2013 7:01 am
Location: North East Ct
Travco Model: 1975 270,1974 220

Re: Travco 270 lost the Hydrovac brake booster

Unread postby Dave78Chieftain on Sat Mar 07, 2015 2:41 pm

To help people understand the RM400/M500 systems easier:

1. When Dodge produced the original M500 chassis in 73/74 they designated it as RM400. Do not confuse that with the M400 chassis as in 73 that was RM350.
In 75 Dodge redefined all this making it retroactive to 73 (described in 1975 Dodge MH Supplement manual). RM350 was redesignated to M400 and the RM400 was redesignated to M500. Can really confuse you if unaware.

2. Aftermarket parts places originally set up their data based on the original RM350/RM400 designation. Many of them did not change over to the 75 M400/M500 redesignation. So again, confusion. That is why I always say start with Dodge P/N for xref.

3. Because a RV manufacture had to ORDER the chassis early from the chassis supplier (Dodge), they normally placed this years model (e.g 1976) on the previous years chassis (e.g. 1975).

4. The original 73 thru 75 Dodge RM400 (M500) chassis ((http://dave78chieftain.com/M500_73-75-RM400.html)) was based on a Hydro-Vac Brake booster system (http://dave78chieftain.com/HydroVac_brakes.html).
Originally Dodge used the Bendix Twinplex system on the RM400 (M500) rear wheels (http://dave78chieftain.com/TwinplexBrakes.html).
Dodge started using to the Duo-Servo system on the RM400 (M500) rear wheels in 74/75 (http://dave78chieftain.com/BXDuoServoBrakes.html)

5. In 76 Dodge converted to the Hydroboost brake system (http://dave78chieftain.com/hydroboost_brakes.html) on the M500 chassis(http://dave78chieftain.com/M500_76.html).

When using my site, access to all of this information is from the hyperlinks at the top right corner where the configuration is described:
M500 (RM400) 1973-75: http://dave78chieftain.com/M500_73-75-RM400.html
M500 1976 and Later: http://dave78chieftain.com/M500_76.html

And finally, when searching for chassis parts, do not search for the term Travco, always use the Dodge Chassis designation
M300 or RM300
RM350 or M400
RM400 or M500
M600

Dave
Dave78Chieftain
Senior Contributor
Senior Contributor
 
Posts: 107
Joined: Sun Mar 01, 2015 5:38 pm
Travco Model: None - Dodge chassis info

Re: Travco 270 lost the Hydrovac brake booster

Unread postby 77Travco on Mon Mar 09, 2015 9:46 am

Once again Dave, thanks for the info...
So my 1977 Travco motorhome probably has a 1976 M500 chassis under it? The reason I ask is because I am curious about my engines compression ratio as there seems to have been a change from 8.2:1 to 7.8:1 in 1977.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1146
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: Travco 270 lost the Hydrovac brake booster

Unread postby Dave78Chieftain on Mon Mar 09, 2015 6:53 pm

For reference:
Both the 73 - 75 and 76 - 77 MH Service manual says 8.12 to 1
78 - 79 manual says 8.1 to 1

Dodge did start to de-tune the engine (carburetor mods and head redesign) to burn leaner in 75 in response to all the emissions tightening. I believe the 75 head redesign was what robbed most of the power.

Locate your dodge VIN number to determine year (6th digit) 1976 = M50DA6S000001 http://www.classicwinnebagos.com/Pages_HTML/DodgeVINdecoder.html#1974

Dave
Dave78Chieftain
Senior Contributor
Senior Contributor
 
Posts: 107
Joined: Sun Mar 01, 2015 5:38 pm
Travco Model: None - Dodge chassis info

PreviousNext

Return to Brakes

Who is online

Users browsing this forum: No registered users and 6 guests