GERALD´S CADILLACS


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DETAILING THE ENGINE BAY AND REMOVING A BROKEN BOLT FROM THE AIR PUMP OF THE 1974 CADILLAC

You can find much more pictures of this project in my 74 restoration gallery.

During the restoration of the battery tray of my 74 Coupe deVille I noticed that the belt from the AIR Pump was a little loose. While I tried to find out how to properly tension it, I noticed that one of the bolts going through the pulley into the pump seemed to stick out a little bit at a strange angle. When I touched it, it immediately broke off… Great…

So I had to remove the pump to be able to get to the broken pulley bolt and replace it with a good new one. It was very common on GM cars from the 70s which used this air pump, that the bolts broke off. GM used 3 very cheap and weak bolts to hold the pulley in place.

Before I took any bolts out to remove the pump, I sprayed every nut and bolt with penetrating oil to make sure I could open them without damage.

I anyway had to take out the AC compressor as well for another winter project. After that I removed the generator and then the air pump including all the brackets.
You can see the at the diagram below where the bolts are hiding.
With these parts removed I now have access to many parts of the engine which I can freshen up to the original factory fresh look. I will remove the surface rust on the block, clean everything and re-paint in the original Cadillac Blue paint.
I can clean the air pump, the generator and will blast the brackets and re-paint them. While the AIR Pump is out you might also want to check the diverter valve atop the smog pump to be sure the vacuum canister holds and hasn't ruptured at the vacuum diaphragm. If the diverter valve does not respond to vacuum, it can lead to all of the positive pressure from the pump being injected into the exhaust stream which can cause a backfire through the exhaust.
Many people also plug the AIR Pump and remove everything inside, so they do no longer have to bother with it. Rebuilt pumps are still available, but you can´t get the diverter valve anywhere.

So it is now officially my winter project to freshen up the engine bay

The air pump is very fragile btw. It's not allowed to put it into a vise. Luckily I could remove the broken bolt with a bolt extractor. I just had to drill into the remains of the stuck bolt a little bit and could then remove it using the left turning extractor tool.

I have now to find replacement bolts now. They seem to be SAE bolts with the following dimensions: 1/4"(diameter)-20(threads per inch) and 1/2" (without the head) long. The original bolts were of the lowest grade material, the new ones I am going to install will be grade 5 or grade 8.

While cleaning the block I decided to also remove the fan and water pump pulley to be able to clean them as well. The pulley was pretty rusty and I had to soak it in rust removing liquid for 48 hours before the rust was gone and I had to paint it immediately as this material develops flash rust immediately.

UPDATE - OCTOBER 28th 2016:


I now also removed the power steering pump to get better access to the front of the engine block. I will also remove the radiator to be able to remove the surface rust underneath. I will then have the entire engine bay dry ice blasted to properly clean everything.

UPDATE - NOVEMBER 5th 2016


I took out the radiator today to be able to clean the surface rust underneath.
I also finished painting all the brackets and the power steering pump which I took down to bare metal before.

You can find much more pictures of this project in my 74 restoration gallery.

As this project is still going on - I will update this posting here soon.

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The engine bay before the start of the project
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AC compressor and generator removed
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The area below the AC compressor will need some good de-rusting, cleaning and detailing
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Here you can see the remains of the broken bolt in the AIR pump
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The AIR pump before cleaning
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The AIR pump after cleaning - some details will still have to be done.edge
First I soaked the removed brakets in acetone to remove the dirt, grime and paint.
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This shows the brackets in the shop manual.
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This shows the brackets in the shop manual.
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This shows the brackets in the shop manual.
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The divert valve which is no longer available. Check the vacuum diaphragm inside while it is out.
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The divert valve which is no longer available. Check the vacuum diaphragm inside while it is out.
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I had to remove the spark plug wires - this is how to put them back correctly.
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The brackets after I removed the paint - soaking in rust removing liquid until all the rust is gone.
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All the brackets and the pulley are now clean, rustfree and ready for paint
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The brackets after painting.
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Rust removing gel in actionedge
Rust removing gel in action - I decided to remove the waterpump pulley and the fan as well after I took this picture.edge
Rust removing gel in action
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Almost clean - one more treatment will be necessary before it is ready for paint. The waterpump was not painted and therefore was pretty rusty.edge
The water pump is now completely rust free and ready for paint.
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I can now fully clean and detail the fan as well. It even still carries the factory stencil.edge
The water pump pulley after rust removal. I had to paint it very quickly because it developed flash rust immediately after removing it from the rust removing liquid.edge
The water pump pulley after rust removal. I had to paint it very quickly because it developed flash rust immediately after removing it from the rust removing liquid. Here it is in black primer to stop it from rusting.edge
The alternator housing after cleaning
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The power steering pump removed
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I took out the radiator to clean up the surface rust underneath…edge
The power steering pump right after painting with wet paint... I took it down to bare metal before painting, but I forgot to take a picture...

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