Power steering box problems.

Gazook · Member

Power steering box problems.

rockylizard · Guru

Gday...

Dunno if this is helpful ... but obtained via Mr Google -

http://www.brettstruck.net.au/c/270886/1/toyota-dyna-coaster-.html

cheers - John

PhillT · Veteran Member

Is there a adjusting screw on that model? Slot head screw with a lock-nut?

If there is, you may be able to get rid of most of the play if it isn't too bad.

Cheers.

Phill.

hako · Guru

Try this link:
au.zapmeta.com/

Alternatively there is a place called Mr Coaster that seem to be experts:

www.mrcoaster.com.au/www/home/

www.mrcoaster.com.au/www/content/default.aspx

Gazook · Member

Many thanks for your replies, good to know I can share my problem and get help.
Phil, there is an adjusting screw for excessive play but this has the effect of tightening the balls on the worm and makes the steering far too tight past the central major wear zone, the steering then doesn't centralise, makes driving twice the effort, tried it already.
Will be checking out the suggested web sites, thanks.

Dale · Member

Gazook Hi Am running a '94 coaster with the same problems you are having. Have you been able to fix it yet ? I put a steering damper on and it improved it a bit. Am determined to fix it once and for all so have the box out now. Have ordered some plus .006'' oversize balls. Dont know whether this will help . The book saids 20thou max end float between the piston shaft my one is about that. Lets know how you are getting on with the problem and I will keep you posted Dale

SnowT · Guru

The Biggest issue with the steering box, is the replacement cost..

I manged to get a secondhand Steering box for a Early model 93... It took me about 2 weeks to find one.. secondhand.. [cost $600] freighted down from QLD Zebra Wrecking..

I'm going to get it Reconditioned and then have it installed..

That is my next job for my bus..

--> Generally Steering Box can Cost a bit for a Seconds unit.. Over $900..

Try not to go the adjustment method as it seems to put further wear on the gear...

MR Coaster Might have what you are looking for..

-- 94 Coaster should be able to get a Replacement for under $1000.. Yes Parts are expensive..

Juergen

-- Edited by SnowT on Wednesday 11th of June 2014 02:11:09 PM

Dale · Member

Snow, Thanks for the advice. After having the box out for a few days and inspecting the parts, I am coming to the conclusion the worm screw is not the cause of the problem and may indeed be a hydraulic problem, eg. the left right valve, or low pump pressure. I am going to pursue down that line. It brings back old days of working on DAC's (DC3's), the main difference is you had good manuals to work from. Regards, Dale

Gazook · Member

Dale, I got a secondhand box from Mr Coaster in Victoria ($900) but still not happy with it, feels like it's worn out too. After a lot of looking I could not find anybody to rebuild the box, only re kit it, Snowt I think that's all you can get done, which doesn't change anything in the box's performance.
Am very interested in your thoughts of a hydraulic problem although I am not sure how that could affect the general play when idle. Let me know what you finish up doing.

I must be just hard to please.

Geoff K.

Dale · Member

Geoff, Thanks for the reply. I've still got the box out and I'm coming to the conclusion that there is nothing wrong with it. The movement in the screw is a function of opening and closing the left right valve. When you prevent this happening by just holding the slotted ramp which opens and closes the valve, there is next to no backlash in the screw. I am waiting for some +.006 thou balls, which I suspect will either jam or not fit in. I now am going to rig up a pressure gauge on the system to check how much pressure is being generated by the pump (I will try and use an oxygen gas bottle gauge which reads up to about 3000psi and the Coaster should be at about 1700psi). Having said all this, I wish before launching into this project, I had carefully checked the steering components for wear, which I suspect is the most likely cause. My Coaster, if say for instance you have to go over a narrow two-way bridge, it is very difficult to keep the bus on a straight course and therefore nerve-racking, which takes the pleasure away from driving it. I suspect, being a long wheel based bus, they are not the most stable and if anything is slightly wrong it will show up when you come to drive it. Your reply gives me confidence to press on with what I'm doing. As it is winter in NZ, there is no pressure on me to have the machine on the road, so I expect I will be working through this slowly and carefully and will keep you posted.

Dale

Dale · Member

Geoff, I've got my steering box back in and just completed 200 mile trip. I don't know why but the steering is a lot better and is acceptable. I haven't actually done anything to it apart from strip the box and pull apart the left right valve and re-assemble. I now have, when I turn the steering a little bit, a slight resistance in the wheel either left or right. Further turning increases the resistance. This happens whether the engine is going or stopped. I am certain that initial resistance is the opening of the left right valve. I am fairly certain that I never had this before. When I turn, travelling slowly, the steering requires very little effort, eg. it appears the power steering is working correctly. If you could put a pair of vice grips on your box that you have taken out, maybe you can check and see if you have that same opening and closing of the left right valve resistance before the pitman arm moves? If I can be of any further assistance, my email is indwebb@clear.net.nz. As soon as I can, I plan to check another Coaster to see if it has the same opening and closing of the valve felt through the steering wheel. When I am driving now, and say there is a bit of camber on the road, I might have the steering wheel slightly over to counteract the camber, but instead of how it was before, having to make the steering wheel hunt (move it back and forth), I can now hold the wheel steady and maintain a straight line.

Dale

SnowT · Guru

Hey Guy's I know this is an old topic but I had better post the results of My Power steering issue's..

As I said I got a replacement Box down from Qld's for $600..
well I had the Box rebuilt for $850 and had it installed while I had some work down to the Bus..

The Job is a success and the Steering is Like it brand new.. [ Mind you I have also had a full front end rebuild done as well.. ] Not a bit of slop in the steering at all..

I'm now sitting on another steering Box, that I'm considering getting rebuilt and possible selling it for about $ 1200-$1300 or just get it rebuilt and store it in the garage for later..

Mr Coaster is Good But, you can not guarantee that the box is in full working order..

--Coaster Parts are not cheap....

So for a cost of $1450 + extra I have a Full rebuilt Steering/suspension system..

Juergen

Dale · Member

Happy to report fixed my coaster steering box by putting oversize balls in. It is very good now on my third attempt fitted .28224'' from Bal-tec in the USA. There is no play on the steering wheel and a dream to drive compared with how is was. Any one need help only to happy indwebb@clear.net.nz Dale

-- Edited by Dale on Monday 21st of March 2016 05:08:06 PM