Howdy all:
My ABS unit on my 240 Volvo has been leaking like brake fluid is going out of style. This is, naturally, wreaking the driver's side fender's paint, and I'm trying to fix the situation.

I purchased one on eBay. Not my favorite thing to do, but the problem I ran into I would likely have not noticed even had I purchased in from a local junkyard. The top two fittings running into the ABS unit are larger than all the other fittings on my car, whereas they are all the same on the unit I got from eBay.

So... I decided to figure out what was going on in the old ABS pump to see if I could possibly switch parts. I found the leak. On the bottom of the unit, there were two giant 24mm plugs. Using an impact wrench, they came off. One side looked good and clean under the plug. The other side was a mess. There is some sort of relief piston under those covers and upon removing the piston, I discovered the cylinder wall was scored, and the corresponding seal was torn up. I'm considering trying to hone the cylinder, and take the piston from the working unit and put it in that.

BUT, the reason I came to the forum: Has anyone taken apart one of these units? I'd like to take the top portion off the old unit, and put it on the new unit. (This is the portion that has the different sized fittings.) But I can't really figure out how it comes apart (I'd really like not to break the units) and I can't find anyone who has (I've been searching around google and the forums, but without much luck).

Anyway, I'm going to be taking these apart somehow, so I'll post pictures. But if anyone has reference, I'd love to see.

Also... at the moment, I don't have full access to my greenbook collections, and will not for a while. I don't think they have information on how to disassemble the ABS unit, but I also can't check.

Thoughts, anyone?

 

So, I dug into the ABS Unit. Here are my findings:

I got got another ABS unit on eBay, that appeared to work. So I removed my ABS unit. Here are the two sitting next to each other.


So, I could tell it was leaking from the bottom. So I took off the giant 24mm cover that are indicated by the arrow.

It looked something like this:

Underneath the cover, there is a spring (not shown) and a cylinder sort of thing. The whole area is vented to the outside. Note that the cylinder's got a threaded interior, so you can stick a screw in it to pull the cylinder out.

One side looked nice and clean, the other side was dirty and had lots of brake fluid in it. Upon pulling the cylinder out, it could be seen that there was crap inside the cylinder area, and it had scored the o-ring and the cylinder wall.

That picture shows the marks on the cylinder wall. The good one, when removed, didn't have such marks. So, I took some 400 and 800 grit sand paper, and cleaned up the cylinder wall. Then I took a good cylinder out of the new one I had purchased, and put it in the old one.

Here is a picture of the bad cylinder:


Oh, it is worth mentioning... why didn't I just put the new one in? Well, the one I purchased on eBay used different fittings than mine.

It is hard to tell from the picture, but the fittings with the blue arrows pointing to them are different from the fitting with the red arrow. In fact, the red arrow fitting is also the same size at the lower fittings also. Anyway, the ABS unit from eBay used only the red sized fittings. This clearly presented a problem. I don't have the tools readily available to flair or properly bend brake tubing, but I do have what I needed to take apart the unit, so that is what I did.

Anyway, the damage to the cars paint was extensive, but fixing bad paint isn't complicated, so I'll just briefly describe what I did with mostly just pictures. Because pictures are my favorite part of any post.
I scraped off all the ruined paint--which the brake fluid had made very easy. But it ruined a lot of paint. Fortunately, it had not rusted almost at all. So, after research, I used Rustoleum: first, two coats of rust primer, then two coats of enamel. I wasn't really too worried about matching the paint, as this is not in a very viable area. My brother recommended Zero rust, and I would have gone with that, except I couldn't find it at all in my area. So, here are some pictures of the damage and process:




























When finally re-assembled, you can barely tell I've done anything.