Power steering fluid leak

Hi, I've been directed here from the New Members Forum.
My Defender 90 had reached the stage when the garage said it was beyond economic repair, so rather than sell it for spares or repair I decided to rebuild it on a new chassis.
Things are going OK so far (except for discovering it had already been rebuilt as a 300tdi rather than the 200tdi it started life as, resulting in some unexpected welding), and I've fixed most of the many faults that had built up over the years. One problem it had was a power steering fluid leak that nobody could find the cause of, and meant me topping up the reservoir every week or so. I've replaced the pipes between the reservoir and the steering box thinking that would do the job, but now I've got it running without the bodywork on you can see that the fluid is coming out of the breather hole in the cap of the reservoir.
I guess this might just be because I've overfilled it, or because I haven't bled the steering box yet, and it may not even be where the previous leak was coming from. I've seen somewhere though that the ZF reservoir has an internal filter and wondered if the problem could be with that?
Anybody had a similar problem in the past?
Yash

it wont be bleeding as box has a feed and return so self bleeds, possibly overfull or pump seals sucking in air is another,

Thanks James. The reservoir is just tied up to the intercooler pipe at the moment so might not be at exactly the right height which could be affecting the fluid level anyway. Are you sure it doesn't need bleeding? Haynes gives instructions how to do it.

Yash said:

Thanks James. The reservoir is just tied up to the intercooler pipe at the moment so might not be at exactly the right height which could be affecting the fluid level anyway. Are you sure it doesn't need bleeding? Haynes gives instructions how to do it.

Click to expand...

as long as its higher than the pump res is ok
haynes isnt a definitive guide by any means, i doubt anyone at haynes ever rebuilt any pumps or steering boxes, any hydraulic system with a return as well as feed will self bleed, oil is circulating all the time from res to pump to box back to res etc lock to lock a couple of times is usually enough

Thanks again, good advice!

Just had the same problem with mine where air being sucked in via the pump shaft seal was aerating the fluid and causing it to expel out through the vent hole in the reservoir cap.
Changed the pump (Br***art so have to wait and see how long it lasts !) and after about 2 minutes of running with a few lock to locks and all air self bled from the system and now good as gold

Thanks, I'll remember that if it carries on after I've checked the level.

I had a leak from mine as well and did all the research to find a replacement pump and thankfully found that the leak was being caused because the inlet bolt at the back of the pump had loosened slightly. Nipped it up and has solved it. If you have to replace the pump there's a Busters guide to doing it on Landyzone.
Finally, my reservoir was leaking from the top as well and it was because the system had been overfilled. I removed some of the fluid to half full and that stopped it. All ok now.

Thanks, I think it may well just be that I've overfilled it but haven't had time to check it yet.

how do I check the fluid level on the reservois is there a max / min mark

muddymaniac said:

how do I check the fluid level on the reservois is there a max / min mark

Click to expand...

there is on the dipstick

muddymaniac said:

how do I check the fluid level on the reservois is there a max / min mark

Click to expand...

cap has a dipstick

many thanks chaps, never had to have the cap off yet, will check level in the morning, thanks again