PSC Steering woes - CBR pump blowing front seal

slravenel · Jan 2, 2018

Little background - Setup worked fine for ~8 rides since buggy was done without any steering issues.

CBR pump, 6" pulley -8 pressure
Double ended ram -6 pressure lines
Remote reservoir -12 feed (and vented 3 sides and down with standard clear poly hose)
21" heatsink cooler -8 feed lines, 3/8 NPT inlet and outlet of cooler
Older orbital (not sure brand, came from a pretty old PSC kit) pics below if anyone knows what this is. I cant remember for the life of me, but I talked to Lance @ PSC before he left and he told me that it was a good load sensing orbital that they used to offer and to keep it as it was better than their current options.

Anyway, this weekend the pump decided to blow out the front seal...it didnt blow it out in a sense that 100% of the fluid came out, but it stopped steering on anything other than flat ground while moving. If you rev it up and turn, the fluid will spray out the front seal. Sitting there, or just idling there and it wont spray out.

I thought it was just a pressure spike from hitting a rock too hard or something...so we went and got a T Bird pump from the parts store (same physical shape and bolt pattern as the CBR), made fittings work, got it bolted all back together as a trail fix..drove it around for about 15 mins and did some light trails behind the shop to test it out...blew the front seal out of that pump too. Same kind of symptoms....wouldnt come out unless revved up and turning; would semi work on flat ground while moving, etc.

Said **** it and left it in the yard where I could back the trailer up to it the next day. Next morning, cranked it up to pull it on the trailer and the sumbitch would steer just fine. Now I know better and know that it will still most certainly blow fluid out the seal if I let it get hot again...but why would it blow out both front seals like that?

I can attest the 2nd pump to being 1) potentially a bad parts store rebuilt pump 2) potentially cavitating and burning itself up (but then also why would the front seal leak if that was the case there)

So my question is:

I assume this is a pressure issue somewhere - Orbital potentially? Line blockage? Coincidence that both pumps blew out the same way? Has anyone else fought an issue like this and have any ideas where to start chasing it down? I would like to not just throw money at pump rebuilds until I can figure out the issue... Could something as small as a kink in the vent line cause that much pressure build up (i cant imagine that it could...I would think it would blow that hose apart WAY before it blew the seal out of the pump)

slravenel · Jan 4, 2018

For anyone wondering - I pulled the plunger and piston out of the CBR and found some light gouging and a stuck piston in there. From talking to PSC, a hard hit can sometimes jam the piston in there and gouge it out...which I had a hit hard enough at Golden Mountain rolling off Jungle Wall to bend a steering arm, so I am going to guess that is the culprit. The pump was just wounded and it was only a matter of time before it went out.

the 2nd pump probably never stood a chance with the high pressure plunger in it from the CBR (and chalking it up to being a POS parts store pump)

but for spare and get back to the trailer sake.... a Tbird pump with some fitting work WILL steer and at least get you out of the woods if you are running a CBR pump.

tallnate · Jan 4, 2018

Seems odd that your parts store pump blew out the same way so quickly. I'm kinda wondering if something internally in your orbital might be tweaked after it took a shock load of fluid pressure during your jungle wall incident.

I've witnessed orbitals do some weird stuff before.. Several months ago a friend of mine was turning into a creek bed trail and somehow a stick made it's way behind the tire and over the frame to the orbital. It sheared off one of the pressure lines and fluid spewed everywhere. So no big deal, we rebuilt the line and hooking everything back up but were never able to get the steering to work again. Evidently the shock load of pressure released caused something to jam in the orbital itself. Drug it back to camp, installed a new orbital and the steering worked perfectly again.

If you blow out another pump, I'd definitely try a different orbital.

slravenel · Jan 4, 2018

tallnate said:
Seems odd that your parts store pump blew out the same way so quickly. I'm kinda wondering if something internally in your orbital might be tweaked after it took a shock load of fluid pressure during your jungle wall incident.

I've witnessed orbitals do some weird stuff before.. Several months ago a friend of mine was turning into a creek bed trail and somehow a stick made it's way behind the tire and over the frame to the orbital. It sheared off one of the pressure lines and fluid spewed everywhere. So no big deal, we rebuilt the line and hooking everything back up but were never able to get the steering to work again. Evidently the shock load of pressure released caused something to jam in the orbital itself. Drug it back to camp, installed a new orbital and the steering worked perfectly again.

If you blow out another pump, I'd definitely try a different orbital.

Yea that was my second thought as well. This orbital is old and has been on my last 2 buggies, so it has seen some use and abuse over the years. I thought about going ahead and pulling it and dropping it off at the hydro shop and have them go through it too...but havent really decided if that is my play just yet or not.

Either way, yes...if I lose another pump, I am going to most likely replace the orbital with a newer unit.

I thought it to be pretty strange myself that they both lost the front seal, but was assured that heat can make these things do a lot of funny things...and that a parts store pump has a better than nothing chance of being junk from the get go laughing1

paradisepwoffrd · Jan 4, 2018

Yeah sadly you are better off finding a low mileage one from a junkyard vs a reman parts store pump.

Esp if you are buying a factory pump that might be introduced, like the WJ pumps.

I was going to guess the pressure relief in the pump was stuck, and you swapped it into the new pump with the output fitting. Pump didn't go into bypass and blew out a seal.

Hudson1 · Jan 4, 2018

I had the same problem damaging pumps and making heat. I now have a CBR pump from PSC with no flow control, and an external pressure relief. No more issues and greatly reduced the heat produced. I like to hit stuff and kept damaging my pumps.

slravenel · Jan 4, 2018

paradisepwoffrd said:
Yeah sadly you are better off finding a low mileage one from a junkyard vs a reman parts store pump.

Esp if you are buying a factory pump that might be introduced, like the WJ pumps.

I was going to guess the pressure relief in the pump was stuck, and you swapped it into the new pump with the output fitting. Pump didn't go into bypass and blew out a seal.

Only reason I now have the parts store pump is just for a spare to get me to the trailer if need be. And it will do that (even when leaking it was still somewhat steering where as the psc CBR was dead as ****.)

I had that same feeling myself thinking I moved it over...but I confirmed that only the fitting itself came out of the parts store pump when I opened it back up.

slravenel · Jan 4, 2018

Hudson1 said:
I had the same problem damaging pumps and making heat. I now have a CBR pump from PSC with no flow control, and an external pressure relief. No more issues and greatly reduced the heat produced. I like to hit stuff and kept damaging my pumps.

This is actually interesting...I have heard of this before but didn't even think about trying it until you mentioned it. I will talk to the pros about this and see if it's an option for me. Adding in a relief in line isn't terribly difficult and I would love to have as little heat and moving parts in there as possible

paradisepwoffrd · Jan 4, 2018

Re: Re: PSC Steering woes - CBR pump blowing front seal

Hudson1 said:
I had the same problem damaging pumps and making heat. I now have a CBR pump from PSC with no flow control, and an external pressure relief. No more issues and greatly reduced the heat produced. I like to hit stuff and kept damaging my pumps.

I'd like more info on this also. By no flow control, you mean there is no pressure bypass spring in the outlet, or something else?

Hudson1 · Jan 4, 2018

Correct. The "factory" style pump has a tiny bypass hole. The fluid when bypassed just recirculates inside the pump. This builds heat. The pump with no flow control, just pumps fluid, no recert building heat. The external flow control valve, by passes any pressure above the set psi back into the the reservoir. If you take a big hit, the valve keeps that hit from making it into the pump. I have had this set up for a little over a year now, no issues so far.

Bebop · Jan 5, 2018

That's what Jesse Haines runs on his 4WS moon buggy and he's happy with his as well.

slravenel · Jan 5, 2018

Hudson1 said:
Correct. The "factory" style pump has a tiny bypass hole. The fluid when bypassed just recirculates inside the pump. This builds heat. The pump with no flow control, just pumps fluid, no recert building heat. The external flow control valve, by passes any pressure above the set psi back into the the reservoir. If you take a big hit, the valve keeps that hit from making it into the pump. I have had this set up for a little over a year now, no issues so far.

Do you have pics of how you set that all up? Are you using any special kind of flow control, or just a regular old hydraulic shop control valve? Did you do the work to the pump, or have PSC do it?

Hudson1 · Jan 5, 2018

I will get some pics of mine today. I used PSC pump and flow control valve. To be honest, I don't think they promote it because they would not sell as many pumps.

1tfrot · Jan 5, 2018

Hudson1 said:
I will get some pics of mine today. I used PSC pump and flow control valve. To be honest, I don't think they promote it because they would not sell as many pumps.

thank you.

and maybe I missed it above, but does this mean there's no "bypass feel" then? mine seems to bypass to easily.

sleepsontoilet · Jan 5, 2018

Hudson1 said:
I will get some pics of mine today. I used PSC pump and flow control valve. To be honest, I don't think they promote it because they would not sell as many pumps.

If I remember correctly it was like $850 for that pump and external relief valve when I was quoted for the system Jesse runs.

Hudson1 · Jan 5, 2018

I have no bypass feel. The external relief valve has bigger moving parts that react quicker. The return valve hole is gigantic compared to a factory pump. The relief valve is adjustable for what you need. If I remember, mine is set at 1250 psi. I am not promoting PSC over Howe, they both have these valves. I have a Howe double ended ram and orbital valve, PSC CBR pump and relief valve. I have a LS motor using a Goat built bracket to locate the pump higher out of the way of my upper links. A factory pump bypasses most of the time above 3000 rpm is I remember. So I my motor, it was making heat because I have a habit of spending the day at 5000 rpm

tallnate · Jan 5, 2018

Hudson1 said:
I will get some pics of mine today. I used PSC pump and flow control valve. To be honest, I don't think they promote it because they would not sell as many pumps.

Definitely some good info being shared on this thread. As I was reading through the previous posts about pumps with no flow control and the external bypass setup my first thought was why isn't this the norm. But yeah, less pump sales could definitely be the reason this option isn't pushed.

slravenel · Jan 5, 2018

tallnate said:
Definitely some good info being shared on this thread. As I was reading through the previous posts about pumps with no flow control and the external bypass setup my first thought was why isn't this the norm. But yeah, less pump sales could definitely be the reason this option isn't pushed.

From what I was told today by who some consider to be THE steering guy - the reason its not more of the norm is that it can come with its own set of finicky issues. Says that if you are racing (or spending most of the time at high RPMs) those setups are the pinnacle of it. But they are $$$, require pretty much a whole new setup, require more space, and pumps "should" be rebuilt every few races in order to stay the pinnacle.

For me, I am limited on space with the buggy being so small. You've seen it...you know it doesnt have a whole ton of extra space. Under the hood is even tighter laughing1

I am going to lower the pump, run the rebuilt CBR, move the reservoir closer and on top of the pump (which i can do now with the new bracket) and try again. If I have more issues, then I will consider a total system overhaul...but I would prefer to not throw endless money at it just yet if I can help it

tallnate · Jan 5, 2018

slravenel said:
From what I was told today by who some consider to be THE steering guy - the reason its not more of the norm is that it can come with its own set of finicky issues. Says that if you are racing (or spending most of the time at high RPMs) those setups are the pinnacle of it. But they are $$$, require pretty much a whole new setup, require more space, and pumps "should" be rebuilt every few races in order to stay the pinnacle.

For me, I am limited on space with the buggy being so small. You've seen it...you know it doesnt have a whole ton of extra space. Under the hood is even tighter laughing1

I am going to lower the pump, run the rebuilt CBR, move the reservoir closer and on top of the pump (which i can do now with the new bracket) and try again. If I have more issues, then I will consider a total system overhaul...but I would prefer to not throw endless money at it just yet if I can help it

Gotcha, so it ends up being a fairly expensive setup all said and done. And if it requires more space I could definitely see that being an issue with how compact your rig is. Hell, my junk has so much crap mounted everywhere.. don't think I'd be able to keep half of it if I had a narrowed chassis. But, I still want one! :eat: