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Topic: P30 chassis master brake cylinder??

Posted By: pkunk on 01/28/09 01:57pm

For the 3rd time in a year the master cylinder has sprung a leak. The first mechanic to work on it finally replaced the hydroboost as well but now we wonder if he had any idea of what he was doing. I now have a better mechanic who know quite a bit more about this system and said that A) maybe the hydrobost pushrod was not adjusted properly, and
B) that maybe the wrong master cylinder was installed.
I need to find the proper part # for my '89 P30. Any one have knowledge of how to go about getting this?


1999 Coachman Mirada 34 ft.V10-F53 chassis
12ft.LR slide-2 gp31 AGM 12V @220AH



Posted By: garry1p on 01/28/09 02:02pm

On my 1990 P-30 I have found that every part I have needed so far turns out to be the same as a;

1990 GM P-30 Van


Garry1p


1990 Holiday Rambler Aluma Lite XL
454 on P-30 Chassis
1999 Jeep Cherokee sport



Posted By: tom_kat on 01/28/09 02:11pm

sometimes theres a listing for MH only but most of the time p-30 parts are the same but need to match the same style/shape as the old one,theres is some differances in bore size on master cyclinders if you use the wrong one,


1985 Class A Holiday Rambler Imperial 33 +1979 Class C Holiday Rambler Statesman 1000 = 24 ft



Posted By: past-MIdirector on 01/28/09 02:49pm

If your using a Borg Warner master cylinder then good luck. My tech installed 2 in 3 months last Summer before he got one that didn't leak right away. They would not tell him why the seals went bad in the first two but my MH is sitting in storage till the snow melts around it and then it's going back in the shop for him to change this one cause it's lost fluid just sitting out in the cold. It's a 91 P-30. I have the original records and it had 2 master cylinders changer under warranty when it was new by Chevy and one when I bought it 10 years ago by the dealer.






Posted By: pkunk on 01/28/09 02:58pm

MI Director wrote:

If your using a Borg Warner master cylinder then good luck. My tech installed 2 in 3 months last Summer before he got one that didn't leak right away. They would not tell him why the seals went bad in the first two but my MH is sitting in storage till the snow melts around it and then it's going back in the shop for him to change this one cause it's lost fluid just sitting out in the cold. It's a 91 P-30. I have the original records and it had 2 master cylinders changer under warranty when it was new by Chevy and one when I bought it 10 years ago by the dealer.

Were those rebuilts? We're thinking that some of them have been rebuilt too many times, that new is the best way to go.
That's what happened to mine-working fine and then sitting out there under it's shed, started leaking.
Still looking for a part number, just to be sure. All my phone leads have dried up as it's a year too old for a Vin search.


Posted By: radardog on 01/28/09 03:25pm

There is a particular way that you have to bleed the system. It includes jacking the front of the Motor Home and starting by turning the steering wheel back and forth with the engine off. It is my understanding that if this isn't done properly you will keep having problems. If you contact OLUSEDBEAR on this forum he has all the information you might need on the auto park and brake system as far as the master cylinder goes. On the 89 model the pressure is from the power steering pump, a hydroboost is used with a actuator for the park brake.


The fan always wins



Posted By: pkunk on 01/29/09 07:58pm

I've got a new master cylinder in hand. Hope it's the right one. I'll know for sure tomorrow. My new mechanic used to be the head of maintainence for the States ambulance fleet, so I have faith in him. He has the specs on the Hydro Boost actuator rod length so maybe this time's a charm.


Posted By: Xpltivdletd on 01/29/09 08:28pm

Mill Supply Inc., carries parts for your P37-based MH's "P32" cousins. My project-vehicle is one of those cousins, so I look things up here a lot.

This may be a better way in.

GM made a lot of these systems. The outfit at the links still supports the older ones the General may have dropped. My project vehicle is a 1981 Grumman stepvan with GM HydroBoost amd thanks to these folks it still isn't an orphan.


Posted By: pkunk on 01/28/09 08:30pm

Bump- I need to order one ASAP


Posted By: PeteHalsted on 01/28/09 08:54pm

My 1991 P30 master cylinder was just replaced, the shop receipt has 39309MS as part # but don't know if that will translate to anything or not.

As others have said for the most part if you lookup same year Chevy P30 you will have the right part.


1989 Elite Diesel Pusher
==========================
Gillig Chassis
250HP Caterpillar 3208T
4 Speed Allison MT643
Xantrex Combi 458 2000 watt inverter/charger
HWH 400 Series BI-AXIS Computerized Leveling System
Dish 500 Sat with VueQube 2000
2007 Chevy HHR toad


Posted By: ggardne2 on 01/28/09 09:06pm

If it was me I would try either a medium/heavy duty truck repair business or an auto/truck parts store such as a NAPA that supplies to a medium duty truck repair facility. There are several master cylinders used on the P30 chassis depending on whether you have all disc brakes or a disc/drum setup and on vehicle GVW.


Posted By: MrWizard on 01/28/09 09:35pm

this interesting news/problem, not good, just interesting to know about

our 82 pace arrow 32ft on a p30 never gave us any master cylinder problems ( disc all around )

our current 89 Komfort trendsetter on P30 has 'shown no signs of trouble YET'

i'll file this under 'need to know'


Options, always have options, and the journey goes much smoother
....

Connected thru Verizon with HotSpot WiFi using a Samsung Galaxy Nexus



Posted By: pkunk on 01/29/09 07:33am

MrWizard wrote:

this interesting news/problem, not good, just interesting to know about

our 82 pace arrow 32ft on a p30 never gave us any master cylinder problems ( disc all around )

our current 89 Komfort trendsetter on P30 has 'shown no signs of trouble YET'

i'll file this under 'need to know'

I believe my problem started because of inactivity, then continued because of an inept mechanic and maybe poorly rebuilt parts. Time will tell.....


Posted By: kneal44 on 01/29/09 10:12am

PRECISION REBUILDERS NEAR ST LOUIS CAN REBUILD AND HAS TESTED REBUILT UNITS. YOU CAN CALL THEM 800.325.2690. they helped me rebuilding my midland/haldex master cylinder when the factory would not help with a discintinued unit.


also for those that want to rebuild their own i have other sources for rubber seals and cups and one manufacture that will make seals for $4 each.

the cold weather can make the rubber harder and not seal very good.

it took me 3 months to fix my mastercylinder by the time i got all the parts ineeded.

CAUTION: use only EPDM rubber that is perioxide cured. thats what brake fluid rubber is made of. also as a test i soaked my newly purchased rubber seals in brake fluid for a week. if the rubber swells or gets gummy... its not the right stuff.

contact me if you want sources of supplies i found several rebuilders and most of them are very helpful. good luck


when u play in the sand .... you can get stuck

9-24-08 corpus christi padre island texas. wrecker had to haul me out!
'92 dp 5.9 cummins 190 hp....8mpg yuck!



Posted By: pkunk on 02/03/09 08:20pm

sum1 wrote:

pkunk wrote:

OK, just for the record....New Master cyl. from Napa, part #39309, $145. I works!
Plus at NAPA, you've got a much better chance of talking to a guy who knows better than to look up a muffler bearing for a 1962 Mustang.

Actually, that's what he found when I asked for the MC. I finally looked up the part # on the internet and gave it to him. Whatever works. I took me awhile, but I perservered. There's nothing unusual about a 'muffler bearing' here in NM.


Posted By: pkunk on 02/03/09 05:00pm

OK, just for the record....New Master cyl. from Napa, part #39309, $145. I works!


Posted By: sum1 on 02/03/09 05:55pm

pkunk wrote:

OK, just for the record....New Master cyl. from Napa, part #39309, $145. I works!
Plus at NAPA, you've got a much better chance of talking to a guy who knows better than to look up a muffler bearing for a 1962 Mustang.


Posted By: pkunk on 01/31/09 04:53pm

Well, the local CarQuest parts people got us the wrong master cylinder, so we'll order again. I might get on the road before spring if I'm lucky.


Posted By: sum1 on 01/31/09 01:05am

You're right, Xpltivdletd. HydroBoost is not unique to this chassis type, either. My Chevy Astro Van had it.


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