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ORU's 4 wdb master cylinder upgrade for our trucks

camiswelding

camiswelding

1/2 ton status
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I am suspicious of ORU's 4 wdb master cylinder upgrade for our trucks.... it does not appear to be any different in the photo than an exisiting hydroboost master cylinder. When I called them they wouldnt divulge what trucks it fit (obviously they wanted me to buy it from them)
I looked thru the raybestos book and looked at a couple of chevy 4wdb master cylinders for later model k3500s/P30 motorhome 4wdb chassis (mine is an 89v3500) with hydroboost and they all had plastic reservoirs... and different bores

Anyone know anything about this... any parts guys out there familiar with this conversion. ORU claims after their M/c is installed the brakes are "vastly" better (even with the drum brakes still on) and that the extra pressure makes the pedal much "higher" and much more "sensitive" (IM not convinced at their claim)

I talked to my chevy parts man and he steered me to the p30 master cylinder 4wdb... but it was NOT and direct bolt-in... as ORU's is... ORU's still appears to have a small front reservoir. The p30 motorhome one would fit but the front line was different... and my chevy man thought it wouldnt stop right
http://www.offroadunlimited.com/store/product_info.php?cPath=22_84_107&products_id=246

thanks

cam

Chevy ORU 4wdb master cylinder hydroboost.jpg

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I have ORU's resevoir and noticed a huge improvement on braking with my stock rear drums. As you mentioned the pedal was higher and I lost that crappy chevy squishy brake pedal that I hated. The pedal was higher and way firmer, I like it alot and give it 2.5 thumbs up :grin:

As far as it's origional app, I don't know. The part # was cut out of the box and ground off the outside of the MC when I picked it up.
 
That looks just like the one I have for my Hydroboost set up. The set up is from a 78 K30.

101584.jpg


Parts America has it for $28 + $15 core
 
I saw that the other day too. It looks just like the one in my '90 3/4 ton 'Burb -

10075025xr12ta.jpg


If anyone knows of a difference, I would love to know. Better brakes would be a real plus in the 'Burb.
 
I replaced mine with a Booster and MC out of an 89 K3500, everything was bolt up with the exception of the shaft that goes to the brake pedal, it needed to be extended 3". After the swap I had much much better braking, no more squishy pedal and it catches pretty high up.

mc.jpg
 
Jason....
Since you actually have one Im wondering if you can see any differences in yours.... as the other posters stated it looks EXACTLY like regular hydroboost masters for my vintage,,, ie it looks exactly the same as the one on my 89...right down to the ridge in the bore housing,line sizes etc....
I find it funny they ground off the numbers and cut the numbers off the box.... I wonder if they are trying to pass off a standard hydroboost m/c as being an upgrade... they claim theirs is NEW (do you think yours was?)... When I queried the guy about how would I know what to replace it with if it failed he said... "all the information comes in the box" in other words."we"ll tell you the big secret AFTER you buy ours for $169....

I cant find and 4wdb master cylinder with a small reservoir in the front... I think "theyze b scammin"

Frog...
Nice work on using a later setup...looks sano... however I already have hydroboost and going back to vacuum for me would be a step backwards...

Anyone else have some thoughts on this.... I going to spend some more time on the phone with them...

cam
 
I know it would be a step backwards but figured I would through my 2 cents in for those looking to do similar. ;)
 
The bore sizes are different than stock supposedly. I have hydroboost in my truck and had the M/C like the one above. All I know is after switching from my stock HB m/c to this one it was a night and day difference.
 
any more info on this camsk5? I could use better braking in the suburban as well. Comparing the pics it apperears that the ord's m/c has larger sized ports to me
 
It's probably out of a 1 ton Van. Look around 1995 or so. They often used different bore sizes for the rear brakes. Usually a 1 5/16" or 1 11/32" bore.
 
What is it we're looking for? Not the apllication, but the bore size etc. I have several brake parts books at home. May be able to find one.

IME when a part is presented as ORU appears to be doing it is an obscure application, but can be found. In the case of the Alum. m/c from wilwood, there is no direct application. The basic part is a MOPAR unit, but the piston used is either a one-off or from some other application.
 
What is it we're looking for?
Click to expand...

well for me i am looking to upgrade my brakes but would like to get the parts at any parts store if posible. I have a 85 3/4 ton suburban with 37 inch tires. I have been in some close situations where I have had to jump a curb or sidewalk to aviod a sudden stop. I live in Virginia and I dont believe any one knows how to drive lmao. BTW I am military and not from here :blush:
 
Ok... I bit...
I called ORU and had a long chat with them.... the tech guy claimed they looked for this master for several years and he said it would be hard to find without actually having one in your hand.... there is no number on it....and they wont tell me what it fits (although after I have it in hand Ill do my best to figure it out) and they wont send my box with numbers on it... they want to have everyone play the game.... Since the price was fair for a NEW American made one I bit and bought it.... (Im also installing a 4wdb chevy proportioning valve)

We will see if their claims prove to be true

"ORUS ULTIMATE MASTER CYLINDER" hmmmm Im still skeptical./.. we will see if it passes the ck5 test.... Ill do a review on it


I have been all over the raybestos book and talking to my knowledgable parts man and chevy dealer.... they dont have it figured out.... maybe with it in hand they will recognize it

cam
 
Cam,

What is your application - I assuming stock front discs on a D60 and a disc brake conversion on a 14 Bolt?

What 4wdb prop. valve are you running?

This should be interesting. Can't wait for the results.


Eric M.
 
Is the ORD master cylinder only for hydroboost equipped trucks or can it be used for vacuum assist trucks as well?

Kevin
 
ORU's master is for hydroboost trucks only....

I currently have a d60 with discs of course and a
d70hd...dually with the 13 inch drums ( ALL NEW)

ORU claims even with this setup I will have vastly improved braking and pedal (Im skeptical but Ill give everyone the real world ck5 test and critique)
I had planned on converting to chevy discs in the rear but Im going to convert everything sequentially so I can really see how things get better or are affected....

the proportioning valve is from a later k3500 4wdb truck.... ORU claims it works in conjunction with their M/c for best results... its a stock chevy part and is a bolt in....(75-90 dollars depending on supplier)

After I do all this if I am not satisfied with it then I might consider a complete conversion (master and hydroboost ) from a p30 motorhome chassis... this costs about 500.00 and requires some messaround with shaft length (I think) to obtain the right travel....

the dually dsic kit would be from blackbirds' custom trucks... (randy)... I tried his 14 bolt dually kit and worked thru some issues with him...in the end I liked it very much... and randy was easy to deal with.... rooferbret bought the whole setup from me before I got it on the ground... so Ill get to do it again... this time with the 70hd.... I would say their kits are spendy but VERY beefy... and they are the only game in town for dually's until someone else wants to mockup brackets and figure out the issues (I was going to run a had ebrake and skip the eldo hassles)

we will see... Ill keep you advised

Its a truck thing.... money is not an issue... momma is :blush:

cam
 
camsk5 said:
I currently have a d60 with discs of course and a
d70hd...dually with the 13 inch drums ( ALL NEW)
Click to expand...

I've got the same set up. I'll be waiting for your report! Have you done the prop. valve swap yet or are you going to try the master first, then the prop. valve?

Thanks,

Eric M.
 
Eric... Im doing them together...its what they recommended....
motor is out right now on the stand waiting to go in so I think Ill do the install as soon as they arrive since there is a nice big hole there right now!!!

cam
 
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