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Premium Member
374 Posts
Discussion Starter #181 (Edited)
Steering pump swap
For the most part, the swap was easy. There was a snag though, causing me to stretch the project over 2 days. I reviewed the draining/bleeding sections in both my 1973-79 and 1980-96 Haynes manuals, as well the tips from Redhead's site, though I have yet to pick up one of their gears. Parked out behind my work place, ready to get started:

Propped up the front end on my new lightweight 3 ton axle stands, so that I can steer back and forth:

The old '78 steering pump, ready to face its fate:

Draining the system was a lot cleaner than I expected (thanks Haynes). Basically just moved my return line into a bottle and turned the wheel back and forth to empty out the line and gear.

Here is the mess that the old system left in my engine bay. It been running all over my front axle, track bar, drag link, and leaving drips everywhere I park. I'm pretty sure in hindsight that I used the wrong type of hose for my return line, because it was spongy and saturated with oil... no good at all.

Old vs new bracket and pump. They sure look similar, right down to same spacing between the axes of the pump and tensioner (I measured, didn't record it though).

Pressure line assembled and read to go in. I used approximately 2 feet of Powerflex hose. For my return line this time I ordered a new stock '78 low pressure hose.

The new setup bolted in, filled with Type F from Castrol. I turned the steering wheel back and forth about 30 times each way, lock to lock, topping up fluid as necessary. Not interested in air bubbles so I went the route of overkill, and moved on to other details during the 2 hour minimum wait time that comes next. Got all the bolts for the bracket installed, and put the pulley back onto the pump:

Premium Member
374 Posts
Discussion Starter #182
Steering pump swap (cont'd)
However, I wrongly assumed that I would be able to use my existing serpentine belt, based solely on the fact that the brackets look so darn similar. I was already pushing the limits of my '94 F-150 belt from the slightly larger pulley on my 3G alternator, and it turns out the E-Series bracket holds the Saginaw pump just a little bit further away than where my Ford pump was placed. I realized this right about the time that the parts stores were locking up for the night, and my Bronco was not in a position to be driven. Rather than accept defeat and wait until morning to resolve the problem at the part counter, I opted to try making my own smaller pulley from some scrap plastic:
78 Bronco, Saginaw steering pump swap (108).jpg

The custom pulley did not solve the problem, so I attempted to modify the tensioner to key into the bracket at a slightly different angle. I had two chances:
  • The original '94 tensioner, which uses a 1/4-20 fastener on its rear face as a key. I drilled and tapped a new hole, but when I went to install the smaller custom pulley, the thread for the idler pulley bolt had stripped. I did not have an appropriate sized tap to re-thread it.
  • The '90 van tensioner, which had a cast-in boss as a key feature. I milled this boss off, and drilled and tapped a hole in the desired spot.
Installation revealed the real source of the problem: the belt line was passing through the center of the tensioner mount, so no smaller pulley or clocking adjustment would fix this. I must have smacked my head somewhere pretty good not to notice this... oh yeah, on the corner of my glove box while it was open. The only solution would be a longer belt. And now that I've ruined two good tensioners, a new one of those too.

Got my girlfriend to pick me up at that point. Next morning I booked a carshare and picked up a belt for a '90 E-150. Comparing to my spare Motorcraft belt (had a Gates or similar installed before, but threw it once, hence the spare), to the new AC Delco one:

Decoding the Motorcraft belt number with help of a graphic from RockAuto:

  • J = belt line
  • K = rib belt
  • 6 = 6 ribs
  • 976 = 97-6/8" circumference
  • C = cog-type design
Applying the same logic to the AC Delco belt:
  • 6 = 6 ribs
  • K = rib belt
  • 990 = 99-0/8" circumference
Tensioners, with the two ruined ones on the left and the new one on the far right:


Still no new drips on the ground at this point... With everything hooked up again, I turned the steering wheel back and forth another 15 times, then topped up fluid, started the engine, and topped up fluid again. Got the Bronco back on the ground and out for a test drive...

The new pump runs great! It can still be heard, but its much quieter than the old one, and I feel a lot better about this one not leaking all over the place. The door is open now for things like hydroboost... once I get the budget together, and after I make the switch to a newer master and RABS.

Premium Member
374 Posts
Discussion Starter #183
After lass than 30km, that AC Delco belt tore itself apart. It was the Friday following my steering swap, after work and on my way to pick up my girlfriend and head back to the island for the weekend. About 5 minutes down the road from my work, my voltage dropped and steering got heavy. I armstrong'd the Bronco into a parking lot, opened up the hood, and sure enough, the belt was wrapped around the fan, with a split down the middle, about 1/3 the belt's length.

I carefully extracted the belt and reinstalled it... yes, I reinstalled an obviously damaged belt. We were trying to catch a particular sailing, and the alternatives would have been to get a cab to the nearest parts store and back again during rush hour, or kindly ask BCAA to bring me a belt. Keeping my revs under 2000 rpm, I made my way to a parts store that was along my original path, got a new belt and installed it in their lot, and continued on my way to pick up my lady. I returned the ruined belt to the parts store the next week, and got my money back. The replacement belt has been working, but squeaking for a few seconds every time on start up. Belt dressing did not help.

A couple weeks later, we went to down to the States to pick up a couple packages, hit Trader Joe's, and fill up on cheap gas. The packages included an ABS headliner and a new Motorcraft serpentine belt ($8 closeout on RockAuto!). It was raining pretty heavily, and we were north of the border, almost home again, when the steering started to cut out. I had full power assist as long as revs stayed around 2500+ rpm. Anything under 1500 rpm was non-assist. I muscled the Bronco home, taking the straightest path I could. To get into the parkade, I had to clutch-in to keep going slow, and rev the engine up to get enough power steering to get around the corners. After parking and letting it sit for a while, power steering returned to normal. I put the front end on stands and cycled the steering, checked for leaks... no problems. It seems as though the Delco belt was slipping in the excessively wet conditions

I swapped out the Delco belt for the Motorcraft one I had just acquired... its a bit dusty and dull looking, but definitely new and still pliable. Comparing the two belts:
  • Per the part number, the Motorcraft belt is 99.5" long, vs the Delco at 99.0"
  • Holding the belts together, the Delco one appears to be about 0.5" longer than the Motorcraft... The Delco may have stretched significantly over only a couple weeks
  • The ribs on the Motorocraft belt appear to be slightly deeper... Rib pitch is the same, but tip width is narrower on the Motorcraft one
  • The Motorcraft belt is marginally thicker than the Delco belt, so hopefully less prone to stretching

While I was under the hood, I swapped out my started solenoid for a new Motorcraft unit. The one I pulled out was also a Ford part, but the studs are not in great shape... cross-threaded and a bit corroded, and the thing has a distinct rattle to it. Not sure if the rattling is really a problem, so I will likely open it up and have a look. Between this, and a new clutch position sensor, my intermittent no-start issue has disappeared (would always start, just sometimes had to try twice).

44 Posts
You are such a professional !!! Really great work and crazy deep dive into things to get it working - or transformed the way you want it to be.
good progress and perfect results which you do present to us!

I will need this thread often I feel, as soon as my 79 arrives from US here in Germany, it will help.
I am really curiously reading through these build threads to create a better understanding of this old Ford tech.
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