We just bought an 84 fleetwood southwind 23' motorhome. The previous owners told us that it was going to need a new master cylinder. My husband has does this before on other vehicles so we thought it would be no big deal. When he got under there it seemed to be leaking where it meets what we are now realizing to be a hydro booster. The booster has a small chip in it so we are thinking that it needs replaced instead. We couldn't find the parts identification sticker and the parts store said that it could be a JB8 or JD7. We still aren't 100% sure which one is ours but we ordered the JB8. Then we started reading up on replacing the part and it seemed way out of our league. I tried to decode our VIN 1GBJP37W4E3340208 per the title which just made me even more unsure. Does anyone know if I got the right part and if this is even going to be a project I can do in the parking lot? I just bought it and haven't even been able to drive it home yet. I also read in the vehicle that we have air coil something or other that should be kept at 50 psi. Where do I check and fill that system? Thank you from a family at its wits end

What chassis is your RV, a Chevy? For info try contacting Geoffrey Rosenburg at Alretta Truck Parts #508-788-9409. He is an expert at older RV brake systems. What about the repair is giving you worries? It isn't much different than doing one on a passenger car. Not sure what you mean by the air coil. Your RV might have air bags in the front springs. Look at them and see. If you have them the air lines are sometimes routed into the front access area. You should see an air line with a Schrader valve on either side. Good luck with your repairs.Miles

What is it leaking?brake fluid or fluid from power steering unit?hydro boosts were usually supplied pressure from power steering pump.if losing brake fluid you need master cylinder.If need hydro unit they are not hard to change ,unhook hoses remove master cylinder rod that actuates hydro unit.when installing check rod length that enters master cylinder.To get correct part check casting number,this should help get proper part.Check with NAPA or brake parts store.

Chassis is a 1984 Chev P37 GVW is 10,001-14000You would need to do a VIN number search to get the correct brake option code.O" Reilly's shows two completely different style master cylinders. O"reillysO'Reilly's shows there is two types of brake booster. Most common for heavy GVW is the hydro boost. Brake boosterYou maybe able to get better idea by looking at photos.

It is leaking brake fluid so we returned the booster and we are replacing the master cylinder. Thank you to everyone and I will keep you updated.

The air coil probably refers to the air bags inside the front coil springs

Please help. 84 fleetwood southwind brakes | Good Sam Community

Son_of_Norway
Explorer
Mar 18, 2015
What chassis is your RV, a Chevy? For info try contacting Geoffrey Rosenburg at Alretta Truck Parts #508-788-9409. He is an expert at older RV brake systems. What about the repair is giving you worries? It isn't much different than doing one on a passenger car. Not sure what you mean by the air coil. Your RV might have air bags in the front springs. Look at them and see. If you have them the air lines are sometimes routed into the front access area. You should see an air line with a Schrader valve on either side. Good luck with your repairs.

Miles
dakdave
Explorer
Mar 18, 2015
What is it leaking?
brake fluid or fluid from power steering unit?
hydro boosts were usually supplied pressure from power steering pump.
if losing brake fluid you need master cylinder.
If need hydro unit they are not hard to change ,unhook hoses remove master cylinder rod that actuates hydro unit.when installing check rod length that enters master cylinder.
To get correct part check casting number,this should help get proper part.
Check with NAPA or brake parts store.
enblethen
Nomad
Mar 18, 2015
Chassis is a 1984 Chev P37 GVW is 10,001-14000
You would need to do a VIN number search to get the correct brake option code.
O" Reilly's shows two completely different style master cylinders.
O"reillys
O'Reilly's shows there is two types of brake booster. Most common for heavy GVW is the hydro boost.
Brake booster
You maybe able to get better idea by looking at photos.
Travelingfam
Explorer
Mar 18, 2015
It is leaking brake fluid so we returned the booster and we are replacing the master cylinder. Thank you to everyone and I will keep you updated.
darsben
Explorer II
Mar 18, 2015
The air coil probably refers to the air bags inside the front coil springs
RLS7201
Explorer II
Mar 18, 2015
Here ya go, Rock Auto brake parts, listed for a P30 chassis. Chevy never made a P37 chassis.

Richard
enblethen
Nomad
Mar 18, 2015
Chev has always made a P-37 3 stands for 1 ton 7 stands for MH stripped chassis.
P-37 info
BrianinMichigan
Explorer
Mar 18, 2015
The air bags in the coil springs may just have the Schrader valve out the bottom of the "A" arm like mine did til I had to replace them. Then I added the air lines to the front of the MH under the hood.
Travelingfam
Explorer
Mar 19, 2015
We got the new master cylinder on and the brakes bled and it is working much better now. I found the air valves for the suspension as well. We still have several op stacked to overcome with this thing though. The generator needs a tune up and coil, neither air conditioners work, the turn signals just broke in the steering column, and the muffler is shredded. Not to mention there are no seat belts, they removed the lp, stove and fridge but put in a small electric fridge and much more. We are having buyers remorse.
turbojimmy
Explorer
Mar 19, 2015
Travelingfam wrote:
We got the new master cylinder on and the brakes bled and it is working much better now. I found the air valves for the suspension as well. We still have several op stacked to overcome with this thing though. The generator needs a tune up and coil, neither air conditioners work, the turn signals just broke in the steering column, and the muffler is shredded. Not to mention there are no seat belts, they removed the lp, stove and fridge but put in a small electric fridge and much more. We are having buyers remorse.

The MC was bad on my '84 P30 when I got it - I assumed from sitting for so long. It made a HUGE difference when I replaced it. My '84 doesn't have any seat belts either - just in the cab.

No offense, but the stuff you mention is easily visible or easy to check before you buy. Remorse could have been avoided. But it's water under the bridge. Hopefully you can make the best of it with the help in this forum.