First oil change & question on skid plate bolts

Did the first oil change on the '03 Tacoma I inherited from my old Dad.

I'll start with a quick rant: Getting to oil pan and oil filter were more of a PITB on this vehicle than any I've ever owned.

Another rant to lead up to my question: Despite the fact that this truck was always serviced by the local Toyota dealership that my Dad bought the truck from, the bolts that hold the two skid plates on were a mess. A couple were missing, no two bolts were the same, and a couple appear to be stripped.

To correct the assortment of bolt types used to hold the skid plates on, I took one bolt to my local O'Reillys auto parts and picked up some M8-1.25 x 25mm hex bolts. So far, so good.

But I discovered that these 8mm bolts are a bit too small for the second skid plate (the one at the rear that is about as strong as a cookie sheet!). The 8mm bolts are pretty loose in the threads they screw into, and if you wiggle them around some, you can push them in and out without turning the bolt.

So I'm wondering if the two bolts that hold the rear skid plate are supposed to be 9mm? And if so, what is the thread pitch?

If that isn't the case, I'll either:

a. Drill out threads a little and tap to 5/16" (I have tap and bolts on hand) OR

b. Toss the two bolts and the skid plate in the garbage

If anyone remembers interchanging the bolts from the front and rear with no problem, that will confirm that they are supposed to be same size and mine are stripped.

TIA for any help on size of those two bolts...

bob

 

M8x1.25 front and back splash pans.
Original bolts had slotted thread ends similar to cutter head sheet metal hex head screws without the hole cutting tip.
I replaced mine with straight M8x1.25 to prevent future wallowing out female threads after two had failed and were drilled and tapped oversize.
5/16" you have on hand is Ok

 

Keep it easy. Drill and tap for a 10mm thread on all the mounts. Go grab a fistfull of 10 mm bolts and nuts with the nylon lock ring. BTW, 9 mm bolts would be a non-standard fastener.

Don't mix SAE and Metric. This just makes servicing the truck a bigger PITA. I've had vehicles with mixed fasteners, never the correct size tool the first time and always fudging around with the wrenches and fasteners. There is enough difference between 1/2" and 12 mm socket to round off a head.

 

There is 0 access to back of pans to put nylok nuts on bolts. Front 3 thread directly into bottom of radiator core support 2 into tranny cross member 2 into engine pan.
Agreed on keeping it easy with metric but OP stated what was on hand.

 

Just remember the lowest paid employee does the oil changes at the dealer on most days.

Those are not skid plates those are tool catchers after I dropped the first ratchet they became scrap.

 

I would just go to your friendly Toyota dealer and buy nine new bolts. They are self-tapping and may save you having to retap the bolt holes. When I bought a few replacement bolts from Lowes, their heads were 13 mm instead of 12 mm like the original bolt heads, and they were somewhat harder to screw in. Probably due to a slightly different thread profile although like I mentioned, the thread size and the diameter of the Lowes bolts were specified to be the same as the Genuine Toyota Parts bolts.

If you do replace them, tighten the ones that go into partially stripped threads very carefully. You don't want to completely strip them out!

Good boy for starting to do your own maintenance!

 

you can buy a "nut sert" tool for as low $30 drill out the stripped holes and make it where all the bolts are the same... it is a real pain in the rear when you have to change 3 socket sizes because the last guy did the simple fix and just slammed the next size bolt it and power drove it home.