Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-25-2019, 01:47 PM   #1
2 Rivet Member
 
1977 24' Argosy 24
SW Florida , Florida
Join Date: Nov 2003
Posts: 67
Images: 8
Need power booster, can't find...24' MH, 1977

Our 24 foot MH needs a power booster. The other half has put in 3 replacements, and each of them locks up the brakes immediately. He is a good mechanic but clueless on a computer, so I am asking for him - where can we purchase the CORRECT power booster for a 1977 24' Argosy motorhome? This is a Chevy 454 on a P-30 chassis.

I did a search on here but got so many hits that I am just starting a new thread. Thank you in advance.
__________________

Elisa is offline   Reply With Quote
Old 03-25-2019, 02:38 PM   #2
Rivet Master
 
bkahler's Avatar

 
1974 20' Argosy 20
Richmond , Kentucky
Join Date: Jan 2003
Posts: 8,036
Quote:
Originally Posted by Elisa View Post
Our 24 foot MH needs a power booster. The other half has put in 3 replacements, and each of them locks up the brakes immediately. He is a good mechanic but clueless on a computer, so I am asking for him - where can we purchase the CORRECT power booster for a 1977 24' Argosy motorhome? This is a Chevy 454 on a P-30 chassis.

I did a search on here but got so many hits that I am just starting a new thread. Thank you in advance.
When replacing the power booster the mechanic needs to make sure he uses the original push rod that is used between the booster and the brake master cylinder. If an incorrect rod is used that could easily be the cause of brakes locking up.

I experienced this exact same problem on a 1984 310 after we had a shop replace the booster and mc. The shop didn't use the original push rod and spent 4 weeks trying to figure out how to fix the problem.

Brad
__________________

__________________
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)
bkahler is offline   Reply With Quote
Old 03-26-2019, 06:47 AM   #3
2 Rivet Member
 
1977 24' Argosy 24
SW Florida , Florida
Join Date: Nov 2003
Posts: 67
Images: 8
Quote:
Originally Posted by Elisa View Post
Our 24 foot MH needs a power booster. The other half has put in 3 replacements, and each of them locks up the brakes immediately. He is a good mechanic but clueless on a computer, so I am asking for him - where can we purchase the CORRECT power booster for a 1977 24' Argosy motorhome? This is a Chevy 454 on a P-30 chassis.

I did a search on here but got so many hits that I am just starting a new thread. Thank you in advance.
Brad, thanks - tell me more. My info/clues: The original pushrod is gone. The original is three-quarter inches shorter than the later model ones. We are on power booster #3 from various sources. So he cut down the newer push rod and it still doesn’t work. It has new brake lines, master cylinder, brakes were bled and a separator used in order to make sure they were bled correctly - I had the privilege of helping with this. The vehicle can be moved as long as the engine isn't on. It locks up as soon as it is started.
Elisa is offline   Reply With Quote
Old 03-26-2019, 11:21 AM   #4
Rivet Master
 
bkahler's Avatar

 
1974 20' Argosy 20
Richmond , Kentucky
Join Date: Jan 2003
Posts: 8,036
Quote:
Originally Posted by Elisa View Post
Brad, thanks - tell me more. My info/clues: The original pushrod is gone. The original is three-quarter inches shorter than the later model ones. We are on power booster #3 from various sources. So he cut down the newer push rod and it still doesn’t work. It has new brake lines, master cylinder, brakes were bled and a separator used in order to make sure they were bled correctly - I had the privilege of helping with this. The vehicle can be moved as long as the engine isn't on. It locks up as soon as it is started.
The original "what" is 3/4" shorter? Where did he get the number to know what size to make the new push rod?

From the description you've given it sounds like he needs to keep shortening the push rod until the brakes don't activate. It would seem your problem is once the pump is running and pressurizing the hydroboost, the hydroboost is pushing the rod towards the master cylinder just enough to activate the brakes.

When the pump isn't running there's no pressure on the push rod so the brakes are released.
__________________
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)
bkahler is offline   Reply With Quote
Old 03-26-2019, 12:07 PM   #5
2 Rivet Member
 
1977 24' Argosy 24
SW Florida , Florida
Join Date: Nov 2003
Posts: 67
Images: 8
Need powerbooster/hydrobooster, can't find...24' MH, 1977

Firstly, I should have said hydrobooster, not powerbooster.



Secondly, the pushrod had to be cut back 3/4". Some other mechanic told him that the old pushrods were 4" long. Ours was 4 3/4", so he cut it to 4". It is still locking up.


How much more should he shorten it from the 4" length it is now?
Elisa is offline   Reply With Quote
Old 03-26-2019, 12:37 PM   #6
Rivet Master
 
bkahler's Avatar

 
1974 20' Argosy 20
Richmond , Kentucky
Join Date: Jan 2003
Posts: 8,036
Quote:
Originally Posted by Elisa View Post
Firstly, I should have said hydrobooster, not powerbooster.

Secondly, the pushrod had to be cut back 3/4". Some other mechanic told him that the old pushrods were 4" long. Ours was 4 3/4", so he cut it to 4". It is still locking up.

How much more should he shorten it from the 4" length it is now?
Just to be clear, we're talking about the push rod (aka output rod) shown on the left side of this picture, correct?

Click image for larger version

Name:	16376373795_8e0a8841d8_b.jpg
Views:	30
Size:	261.5 KB
ID:	336607

Unfortunately that's a question I can't answer. As painful as this may sound you might just have to shorten it by something like 1/16" at a time until it works.

I know it's a pain to unbolt the master cylinder just to get the rod out but I don't know of any other option. I've been doing some searching but having found anything that might described the required length.
__________________
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)
bkahler is offline   Reply With Quote
Old 03-26-2019, 01:32 PM   #7
Rivet Master
 
bkahler's Avatar

 
1974 20' Argosy 20
Richmond , Kentucky
Join Date: Jan 2003
Posts: 8,036
There's some interesting info in this hydroboost thread. Apparently a push rod could be a short as 3.45" on some vehicles.

One thing of not that I read is apparently there is supposed to be a little bit of pre-load on the master cylinder piston, but not a lot. One way to determine how much to remove from your push rod would be to start loosening the bolts that hold the mc to the hydroboost and see if you can figure out at what point the brakes release.
__________________
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)
bkahler is offline   Reply With Quote
Old 03-26-2019, 01:39 PM   #8
Slide Out Society #001
 
GCinSC2's Avatar
 
2007 30' Classic S/O
Somewhere , South Carolina
Join Date: Apr 2010
Posts: 3,365
Might be a long shot might pay off. No clue but try contacting these folks direct.

http://m.cardone.com/
__________________
S/OS #001
2005 Dodge Ram 2500 5.9L 6 Speed
16" Michelins, Hi Spec Wheels, Max Brake, Carslile Actuator, Equal-i-zer, Dill TPMS. Campfire cook.
GCinSC2 is offline   Reply With Quote
Old 03-26-2019, 06:50 PM   #9
2 Rivet Member
 
1977 24' Argosy 24
SW Florida , Florida
Join Date: Nov 2003
Posts: 67
Images: 8
Need powerbooster/hydrobooster, can't find...24' MH, 1977

Thank you all - our next day to try will be Thursday. I will push the brake pedal while he is underneath figuring out the push rod/master cylinder/brakes as y'all stated.


Yes, Brad, that rod in the center of the cylinder in your photo is what I am calling the push rod.


Cardone didn't have what we needed, as I recall. The chassis is a P-30 Chevy from 1977.



We have been fooling with this for quite a few months. Other than this brake system update, the motorhome is fabulous - now.
Elisa is offline   Reply With Quote
Old 03-27-2019, 07:19 AM   #10
4 Rivet Member
 
GREEN ARGOSY's Avatar
 
1977 20' Argosy 20
Matsubushi , Saitama
Join Date: Oct 2018
Posts: 290
Click image for larger version

Name:	IMG_6921.JPG
Views:	34
Size:	351.7 KB
ID:	336658
Here's an output rod which was removed from my Argosy's hydroboost.
My Argosy is 1977 20' model with Chevy 454 motor.
I don't know it's the OE hydroboost but it had worked well (At least never locked) a long time ago.
(Because my argosy is sleeping for about ten years..)

A vernier caliper says "4.8 inch "

Click image for larger version

Name:	IMG_6957.JPG
Views:	22
Size:	314.4 KB
ID:	336659
And the rod is sticking out about 29 to 30mm from their mounting surface.
Sorry, I'm not familiar with SAE. I should have said "about 1.1 inch".
Moreover I can't say that with imperial measurement.
That's too difficult for me..

Click image for larger version

Name:	IMG_6937.JPG
Views:	23
Size:	409.9 KB
ID:	336660
This is a remanufactured hydroboost that I'm going to use for the Argosy in the near future.
Yes, I know it. That is not same shape as the original one.
But the manufacturer said "it would work for 1977 P30 even if the shape is different." I'm doubting it, but should believe them..
I don't have any options..

Fortunately, the vernier caliper says the similar value as the old one.
However I can't say that the new hydroboost would work well on the Argosy. Because I haven't installed it yet.

Thank you, Yuki
GREEN ARGOSY is offline   Reply With Quote
Old 03-27-2019, 08:21 AM   #11
Rivet Master
 
bkahler's Avatar

 
1974 20' Argosy 20
Richmond , Kentucky
Join Date: Jan 2003
Posts: 8,036
Quote:
Originally Posted by GREEN ARGOSY View Post
Attachment 336658
Here's an output rod which was removed from my Argosy's hydroboost.
My Argosy is 1977 20' model with Chevy 454 motor.
I don't know it's the OE hydroboost but it had worked well (At least never locked) a long time ago.
(Because my argosy is sleeping for about ten years..)

A vernier caliper says "4.8 inch "
Yuki, your information should be just what Elisa is looking for. Elisa's Argosy is a 78 and to the best of my knowledge there should be no difference between a 77 and 78. I do know there were differences between 74 and 76, but after 76 the system pretty much stayed the same until the larger coaches were built. Even then I believe the parts were probably interchangeable.

If it was me I'd cut down the 5" rod to 4.8" and give it a try.

Brad
__________________
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)
bkahler is offline   Reply With Quote
Old 03-28-2019, 04:21 PM   #12
4 Rivet Member
 
GREEN ARGOSY's Avatar
 
1977 20' Argosy 20
Matsubushi , Saitama
Join Date: Oct 2018
Posts: 290
Quote:
Originally Posted by bkahler View Post
Yuki, your information should be just what Elisa is looking for. Elisa's Argosy is a 78 and to the best of my knowledge there should be no difference between a 77 and 78. I do know there were differences between 74 and 76, but after 76 the system pretty much stayed the same until the larger coaches were built. Even then I believe the parts were probably interchangeable.

If it was me I'd cut down the 5" rod to 4.8" and give it a try.

Brad
Brad,
I am glad if my post would help them.
__________________

GREEN ARGOSY is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need P30 Brake Booster, 1977 24' MH Elisa Argosy Motorhomes 1 12-07-2018 08:22 AM
Cell booster power draw? Bradknapp Boondocking 3 07-29-2017 10:49 AM
Power Booster for TV SGT DAVE Sprinter and B-van Forum 17 05-12-2013 05:33 PM
Trying to find Grandpa's Old Airstream...can I find it with Serial Number?? Jakescheid Our Community 13 11-22-2011 11:01 AM
Where is the TV Antenna Power Booster - 2005 Classic? classic67 2001 - 2005 Classic 9 07-29-2006 07:58 AM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 08:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.