Hydroboost P/N's 2770317 vs 2770209

[dconn22]

I have searched to no avail so here goes, the 317 is listed for [only] the M1009 [K5] and the 209 is listed for all others [K30, M1008 in my case]. all of the sellers I have located seen to used these P/M's as interchangeable and or list only one for both. It also appears that at some point the 209 was superseded by 2771250 but not positive [may just be a "suitable substitute". I did see in the -34 that the 209 has a slightly larger piston [connected to the pedal] than the 317 [.600 vs .668 I believe it said] and there was stuff about the housing being tapered for a rubber boot on one and not the other [don't think that is too big a deal]. I ordered a 317 from EPS [before I found all this out] because it was listed for the M1008 [I have made an inquiry with them].
Who's got the true low down on this.

 

[ZiggyO]

My understanding (as related to me from a CSMS mechanic years ago in Bordentown, NJ) was that if you used the 1008 booster on a 1009, you would go through the windshield when you hit the brakes-- the other way around, you would have "ok" braking when running empty but loaded would show a significantly diminished braking capacity. I have never tried it myself, so I cannot attest to that statement's accuracy, but he did say that there was notice about it circulating in their shop when they still actively worked on cucv's and that there was even a ps mag note on it as well.

Z

 

[dconn22]

My understanding (as related to me from a CSMS mechanic years ago in Bordentown, NJ) was that if you used the 1008 booster on a 1009, you would go through the windshield when you hit the brakes-- the other way around, you would have "ok" braking when running empty but loaded would show a significantly diminished braking capacity. I have never tried it myself, so I cannot attest to that statement's accuracy, but he did say that there was notice about it circulating in their shop when they still actively worked on cucv's and that there was even a ps mag note on it as well.

Z

Well the TM's are pretty clear about it but in the "real world" many/most suppliers don't seem to make a distinction about the two. I was just thinking [oh no!] that the booster is not really "The Brakes" it only makes it so you don't have to push the pedal as hard [for those of us that remember trucks without powerbrakes!!! how did we survive]. So maybe I'm a little less concerned. the -34 indicated the one for the truck had a 1.75mm larger dia piston than the SUV which if my grease monkey engineering degree severs me right would allow a higher multiplication of foot pressure to the master cylinder [or something like that]. The real question here is there an actual supplier and part-number that makes one for a 5/4 ton [I will look into rebuilding mine if the new one is different.
Another fun bit I discovered in my research is the "gold" accumulator s for rear drum brakes and the blue [haven't seen one] is for rear disc brakes [some rebuilders just paint em black...]