throwout bearing carrier, crack?

[oldspert]

I was cleaning the throwout bearing carrier and found this, possible a crack or just casting flaw. It is the same on both sides. Does not appear to go through to the outside.
Ed

[gdmn852]

Hello,from the picture I think the parting line from casting process. It will be a slightly raised area 180 degrees from each other.

[nkaminar]

There are two things on the casting of interest. One is the parting line that is talked about above on the outside of the part. The other is a line on the ID that may be a crack. The way to test is to use a dye penetrant or magnetic flux test.

In the dye penetrant test a fluorescent die is allowed to seep into the crack and then wiped off. A powder is then applied to draw out the die to be viewed with a black light.

In the magnet flux test a magnetic field is applied to the part and iron filings sprinkled on the part. The filings will cling to any area were there is a crack.

Either of these tests will tell you if you have a crack. If you do, I would recommend replacing the part.

[mcgarrett]

Is that a machined surface where the "crack" appears? If it has been machined, I'm thinking there shouldn't be any trace of a casting parting line...unless it really is cracked!

[oldspert]

Originally Posted by mcgarrett

Is that a machined surface where the "crack" appears? If it has been machined, I'm thinking there shouldn't be any trace of a casting parting line...unless it really is cracked!

That is the machined surface that slides on the front bearing retainer of the transmission. There is the same thing on opposite side.
Ed

[JayJay]

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spert - that looks to me like a crack. Good eyes. If it was mine I likely would not use it, but YMMV.

[oldspert]

I had this checked for crack using dye penetrant, showed no full crack, so I appears to be a casting flaw. Installed my new throwout bearing and am ready to go back.
Ed

[Fullraceflathead]

Many times during the casting process you can get a condition called cold flow. I believe that's what you're seeing and it's at the parting line area in this case. Yes since it was tested for cracks and found to be not cracked I would think that it's just a little bit of a cold flow in the material and nothing to worry about. If this was a highly stressed part it may be a concern. The way the part it used it’s not seeing much stress at all at the parting line area. The slight press fit of the bearing is probably the most stress this casting would see and it is in compression it’s not trying to separate the material at the parting line.