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Power steering 72 Mach 1


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Hi All,

I am in the process of restoring my 72 Mach1 Q code and wanted to get other opinions on either restoring my original power steering or upgrade to the Borgeson steering box ? As I’m a bit short on cash I would prefer to restore my original what are your thoughts ?

also should I try to restore my disc brake power booster and master cylinder or replace with new ?

looking forward to receiving some replies

Terry 

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I say restore.

I simply repainted my power brake booster and it was fine.

The ps boxes are a standard.  I used Power Steering.com in Missouri and am happy.

Unless you are doing something crazy with your driving, the original equipment is good to go.

kcmash

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As you live in Australia, getting parts to do a PS rebuild yourself might be quite a bit harder than on this side of the Equator plus it isn't that easy to do without some technical know-how and proper tools. So, unless there is qualified shop within a reasonable distance that has the knowledge and parts to properly rebuild a Saginaw 800 PS box, (it should be a variable in a Mach1, tag ID SPA-T or V) my suggestion would be to buy a quick ratio 12.7:1 from one of the US companies. I suggest doing some research as I can't offer an opinion as to which would be best. Most remans I've seen are all fixed ratio 17.5:1, you need a variable ratio16:1-13:1. I have not done the PS pump myself, so I can't offer anything on that score. Brake booster can be checked with a vacuum pump and the appropriate plug fitting. Pull the check valve out, install plug and apply vacuum. If it holds for say 5 mins, should be good to go. Check the check valve simply by doing the suck-blow test, you should be able to suck air in the direction of the vacuum flow, but not blow back through it. If that's all good, check your hose, if bad replace. Hope that helps.

Good luck with it.

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Geoff.

 I learn something new every day!

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Rather just an edit, I was rethinking my comments above. 

If you have good mechanical skills, a rebuild seal kit is available from Rock Auto or many other vendors, is not expensive. It is not that hard to take a PS box apart, but you need to do your research on the process. There are many videos on YouTube, some are crap, other ok, but that is how I learned to do mine. It's not getting it apart and cleaned up, it's getting it back together with correct preloads. There has been a lot posted on rebuilding. The main areas of concern and why you may have to buy a new or rebuilt, is wear at the seal area on the sector shaft, (which will need to be machined and hard chromed) and wear inside the rotation valve body due to the 3 teflon seal rings wearing into the casting. If these wear groves are more than a few thou deep, (.003-.005") it may not work at it's best. In the v/r box, there are 24 balls, 12 are very slightly smaller and these MUST be reinstalled alternatively. If you have excessive free play on your steering wheel, more than 1" either way, these balls will need to be replaced with larger ones. Ford used to sell ball kits in 5 different sizes, but now nla. These balls measure to 5 decimals but I found from a rebuilder that various sizes can be bought from specialist manufacturers. At this point, if your box is too worn out, you will need to buy a replacement or have yours professionally rebuilt. Saginaw PS boxes are a GM product, used extensively on many GM products, so there's a good chance that you can find a rebuilder near by. Parts from several GM cars can be interchanged and it is possible to build your own fast ratio box.

Not wanting to overwhelm you on this, but steering is not something to play with. Other parts to check in your steering system are the drag link, tie rod ends, pitman arm and idler arm. some or all of these may need to be replaced as well. When you do an alignment for radial tires (tyres) I had mine set at 1/16" /side toe in, 3 degrees castor, camber; left 0.5 * right 0.8* which is pretty good I found.

All of the above is from what I have learned over the last few years and not expert advice. It's up to you to decide what is best for your budget and experience. There are several members with lots of knowledge, Bentworker being one of them. Ask questions.

First pic is the rotation valve assembly, second is sector shaft that has been hard chromed and ground (about 1" up from splines)

 

IMG_0755.JPG

IMG_0756.JPG

Edited by Stanglover

Geoff.

 I learn something new every day!

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16 hours ago, Terry said:

Thanks great advice, I will attempt to rebuild the box with a rebuild kit from NPD in the U.S. they deliver to Australia in a couple of weeks,  I will update my progress. Cheers.

 It is doable, BUT take you time on reassembly. Watch You Tube videos. Like I said, some are total crap, the guy(s) have no idea what they're doing, others are really good. That's how I learned at the start. My background includes being a machinist, so I was able to get my sector shaft repaired, but if yours is scored up at the lower seals, you'll probably going to have to send it out. If only Saginaw had put a dirt seal before the pitman arm, this likely would not be such a problem.

I'll shoot you a PM with more details and tips than I can put here.

If you order a rebuild kit, get the one with the sector shaft and input shaft bearings., plus, for the cost and your location, I'd order a second (no bearing) kit as well. It's way too easy to f up the rack piston seal and you ONLY get one.

Geoff.

 I learn something new every day!

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I’ll second what Geoff said about the kits- order 2.  Also Rock Auto has them for a decent price.  Once I get on my laptop later today I’ll post some literature from Saginaw that will help out.  You do need to get a dial or beam style inch pound torque wrench (0-30 to 0-75 inch pound range... NOT a click style)

 

 

Saginaw-800-PS-Comp.pdf

Pages from Sag800-Service.jpg

Sag800-Service.pdf Pages from Sag800-Service.pdf

Edited by Bentworker
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12 minutes ago, Bentworker said:

I’ll second what Geoff said about the kits- order 2.  Also Rock Auto has them for a decent price.  Once I get on my laptop later today I’ll post some literature from Saginaw that will help out.  You do need to get a dial or beam style inch pound torque wrench (0-30 to 0-75 inch pound range... NOT a click style)

 

Good call on Rock Auto, that's where I get mine, Edelmann 7860,  without the bearings. or 7858 with bearings, but Terry should check their website, I'm sure they ship to Aus. 

The beam gauge I got is 0-80 in/lbs and I think I got it off Amazon. As we know, setting the preload is critical so as not to overtighten the sector shaft. Also made up a socket from a scarp rag joint. The wrench I made is not totally necessary, but handy.

IMG_0766.JPG

IMG_0762.JPG

Geoff.

 I learn something new every day!

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  • 1 month later...
55 minutes ago, Terry said:

Thanks great advice, I have now rebuilt my gear box all the internals we’re in great condition. Thanks for you help

doing the diff next.

Terry

 

That's great Terry. I was wondering since we'd not heard from you lately. Glad you found the internals in great condition.  That's a rare thing.  As for the Diff. you're on your own as far as I'm concerned.

Edited by Stanglover

Geoff.

 I learn something new every day!

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