Exploding Power Steering Box!!!
 

Anyone ever have this happen to them?

Just rebuild my power steering box cause the end cap seal was leaking. Got everything all cleaned and back together. Was bleeding the system, turning lock to lock, and on about the 3rd cycle heard a loud pop and metal clank. Found part of the end cap on the ground with about a quart of brand new power steering fluid. Retaing ring and the rest of the cap is still in the box. I have never seen on of these caps explode like this.

Anyone seen this before? Anyone know where I can get a new end cap?

Ofcourse we are leaving for Hot August Nights next Saturday so this is not the most opportune time for this to happen.

Re: Exploding Power Steering Box!!!
 

Summit racing has brand new not rebuilt steering box’s.

Re: Exploding Power Steering Box!!!
 

Can you post pictures of where on the power steering box that piece came from?

Re: Exploding Power Steering Box!!!
 

Were you "two-blocking" the steering gear? Holding the steering hard on the stops generates serious high pressure, which usually bursts the high side hose first.

Re: Exploding Power Steering Box!!!
 

I will try and get a picture when I get back home. But it is the center section of the big aluminun cap at the end of the steering box.

Re: Exploding Power Steering Box!!!
 

I was trying to bleed the steering. Going from lock to lock. I didn't hold it hard at a lock stop or anything. Nothing different then when I originally installed the box 2 years ago.

Re: Exploding Power Steering Box!!!
 

This thread in the link below a member had a Similar experience.

Link: https://67-72chevytrucks.com/vboard/...+cap+explosion

Re: Exploding Power Steering Box!!!
 

Properly bleeding the system does not require the engine to be running, only having the front wheels off the ground.

Re: Exploding Power Steering Box!!!
 

Huh. I worked on vehicles for decades and never knew that. Learning all the time!
As for having them off the ground, I can think of two reasons- easier to turn the steering wheel, and not scrubbing flat spots on the tires.

Re: Exploding Power Steering Box!!!
 

That is news to me. I always thought you needed the pump running to get the fluid to circulate.
Well, I guess I will bleeding it in the next round with OUT the motor running.

Thanks for the heads up.

Re: Exploding Power Steering Box!!!
 

Here is a better picture of the part that failed.
Part on the left is a good one I was able to harvest from another box I luckily had laying around.
Part on the right is the failed part (obviously)

Second picture of where it installs on the steering box (already harvested the cap)

Re: Exploding Power Steering Box!!!
 

So got the "new" cap installed and followed Rustypile's advice and bleeding it without the motor running (wheels still off the ground). Lock to lock 10 times, topped off fluid at 5th cycle and again after 10. Then started the engine and did 75% left and 75% right (was gun shy) about 10 times. No issues. Dropped her on the ground and took her for a test drive, works great, no groans, no noises, best of all the cap did blow off again.
Thanks for everyone's advice.

Now I need to find another end cap so I can rebuild my spare box and have it ready for a future project. Anyone got one laying around or a junk box they would mind parting with the end cap?

Re: Exploding Power Steering Box!!!
 

What is the screw in the middle of the broken cap?

Re: Exploding Power Steering Box!!!
 

Yes, inquiring minds want to know

Re: Exploding Power Steering Box!!!
 

That was my addition. Because I was frustrated with the fact I had to tear the entire box back apart just to replace the cap o-ring I had added it to the cap incase the it leaked again and I had do do the o-ring again. Give me something to grab and pull the cap off with from the outside of the box. It didn't have anything to due with the failure, there are no marks on it or cracks emanating from it. Before I put it back together I made sure the it did not come into contact with the piston.

I think my failure was due to air in the system (I had stupidly started the engine with little to no fluid in the pump reservoir) and going full lock with that air in the system.

Re: Exploding Power Steering Box!!!
 

I also worked on 'em for decades. I spent countless hours at the GM training center in Houston, Texas in the '60s and '70s.. When I went to "steering school", that was the first thing I learned.. Also, those instructions are included in the box with several aftermarket units. Cardone is one of those.

Just jack up the frond end. Fill the pump reservoir and slowly rotate the steering lock to lock several times. Refill the reservoir as needed. Top off after the test drive.. As it was explained to me, under pressure, the fluid becomes aeriated, and pressure spikes develop. Aeriated fluid is the primary cause of humming and howling noises in the beginning. Flat spotting the tires is not the reason for having them off the ground. Eliminating resistance to the components while bleeding is the reason.

Re: Exploding Power Steering Box!!!
 

>>Cardone is one of those.<<

I had to have the Rack on my C4 Vette rebuilt about 10 years ago. Some of those Racks are extremely rare and the rebuilders do not have cores. They rebuild your rack after verifying that it is rebuildable. NAPA sent my rack back east (Philly maybe) to Cardone.

Their instructions were to DO NOT START THE ENGINE. Fill the reservoir and use a hand vacuum pump, sealed on the mouth of the reservoir. After the fluid level drops, refill and vacuum again.

It works. I have since used that system on a worm gear box and it works.
It doesn't aerate the fluid like other methods.

Cardone claimed they could tell if I didn't bleed it properly and wouldn't honor the warranty.

Re: Exploding Power Steering Box!!!
 

I read the flat spot avoidance reason in my '60 Chevrolet repair manual. Maybe that caution ain't in the books anymore.

Re: Exploding Power Steering Box!!!
 

Two things. First, I did not know about the engine being off to bleed the system. I always thought it needed to be running as well. Second, your cap failed, in my opinion, due to it being a 50 year old plus part and the fact that there looks to be a considerable amount of porosity in the casting. It's probably a blessing that this happened in your garage, rather than out on the road. Glad you were able to get it put back together.

Re: Exploding Power Steering Box!!!
 

Maybe it was a bias tire issue.