|The MGA With An Attitude
REMOVING Main Bearing Caps -- CS-106A
At 11:19 AM 11/14/2009 -0700, Jonathan Dickinson in Nice, France, wrote:
"I'm planning to tackle the crankshaft removal. I have read that I need a slide puller to extract the main bearing caps. Is there a specific type of puller for this job"? I've been looking through my tool shop catalogue and the pullers seem to be designed for bodywork repair.
Any slide puller will work. All it needs is an adapter on the end to screw into an exisiting thread on the bearing cap. Front and rear caps have 1/4-28-UNF threads for sump bolts. The center cap has a larger thread. I think one of the bearing cap studs will fit there. That is a 1/2-20-UNF threaded stud.
Slide hammer kits are all similar, but some have a better assortment of end attachments. See tool article TS-117. One of the most common attachments is a large screw-on cap nut with a 9/32" hole in the end and a 3/8" hex socket inside. With this you usually get a long 1/4" lag screw with 3/8" hex head. This used to be the tool commonly used for pulling dents (but no one in their right mind would do it that way today). If you grouse around a bit you may be able to find a 1/4-28 screw with 3/8" hex head. If not, then use a standard 1/4-28 screw with 7/16" hex head and grind the head down to 3/8" hex size. That will pull the front and rear bearing caps. For the center cap, get a standard fine thread hex head bolt to fit there, then use the 3-jaw puller on the bolt head.
There is another way to do this without a slide hammer, more useful under the car with engine in situ. Screw a long bolt into the bearing cap with a flat washer. Use a big pry bar with a block of wood against the crankshaft to lever the bearing cap out of its nest.
You can R&R the bearing caps under the car if only replacing bearings. For the front main cap you have to remove the two bottom bolts from the timing cover, as those go through the front plate into the bearing cap. Putting it back together requires sealant in place of the end plate gaskets. To remove the crankshaft the engine has to come out, and end plates must be removed. With engine out you can R&R the crankshaft without removing cylinder head or pistons and con-rods.