Rear subframe bolts

[MrChris]

Afternoon all, my MR2 is just about ready for MOT and when I was about to set it back down after being on axle stands for months I noticed two of my rear subframe bolts were not seated all the way in... 

I've taken them both out, one looks okay but dirty and the other has definitely had the threads damaged. How likely is it that the subframe thread will be okay? Provided it is okay, where is the best place to source new subframe bolts?

Thanks again and hoping to update my reader's ride thread with some positive news after this!

[MrChris]

I realising I'm answering my own thread here and so come across as slightly unhinged but... would tap and die on the inner thread and the bolt sort this? Any thing to be aware of?

[MrChris]

And I forgot to check with J-SPEC..! That's done and 4 new bolts on the way. Fingers crossed that the internal threads are okay, he advised to wind new bolts in and out to try and clean the female threads.

[Joesson]

@MrCris

I  had a similar thread problem with the banjo bolt hole in one of the front calipers I was refurbing.
First off I tried putting the bolt in a quarter or half turn at a time and backing off while liberally lubricating with brake fluid, as when using a tap to form a thread. You could use drops of engine oil. That didn't work for me.
I then purchased via the www a suitable tap, these range in prices from very low to Very high. It likely only being used once I bought at the lower end.
You won't need a full set of three taps, mine was a refinishing set of two taps.
My bolt was being replaced, so no need for a die, but I suggest the cost of a die, and die holder if you don't have one, will likely be higher than replacement "bolts".
Yours is most likely a machine screw, where the parallel screw thread runs to the underside of the hexagon head.
If replacing then you need to determine diameter and thread pitch, in a mm size.
A high tensile type, a read on the www again will help decide the grade. Specific Toyota fixings will be costly and no different to commercially available items.
Do you know the history of your car? That fixing is not one that I would anticipate as coming loose, so I would give the other fixings a good looking at. Only remove one fixing at a time, otherwise you could loose alignment.
Let us know how you get on.

[MrChris]

Let us know how you get on.

Thanks for the advice @Joesson - Andy at J-SPEC suggests that the thread is M8 1.25 although he was driving so he said this may not be accurate. I don't have any parts/components of a tap and die kit. Andy seemed to think using lubricant and gradually threading in/out the new bolts he's supplying may be enough to clean/sort out the internal threads. I'll try that first but if not I'll definitely look to do what you suggest.

[Carolyn]

Thanks for the advice @Joesson - Andy at J-SPEC suggests that the thread is M8 1.25 although he was driving so he said this may not be accurate. I don't have any parts/components of a tap and die kit. Andy seemed to think using lubricant and gradually threading in/out the new bolts he's supplying may be enough to clean/sort out the internal threads. I'll try that first but if not I'll definitely look to do what you suggest.

They are M12 x 1.25.  I've had to run a tap through these on more than one car.

[MrChris]

They are M12 x 1.25.  I've had to run a tap through these on more than one car.

Thank you @Carolyn - sounds like I should just get a tap then?

[Carolyn]

Thank you @Carolyn - sounds like I should just get a tap then?

I would.

[Joesson]

Thank you @Carolyn - sounds like I should just get a tap then?

US Pro is the brand I bought.
https://www.ebay.co.uk/itm/144216409673?
If no tap wrench you could try a suitably sized open end or maybe a ring spanner  or multi point socket if your lucky, that suits the square end . You won't need the full advantage of the tap wrench to refinish the thread. You will likely need to use the tapered tap to get a good start on the thread. Dipping the tap in a drop of oil won't go amiss.

[Call the midlife!]

Drop of oil, impact wrench, senddddddd ittttttt!

[Carolyn]

Drop of oil, impact wrench, senddddddd ittttttt!

Make damn sure you've got it started straight before you do that!!

[MrChris]

Drop of oil, impact wrench, senddddddd ittttttt!

Lol  I must confess... This miiight be the reason I'm in this situation...

[MrChris]

US Pro is the brand I bought.
https://www.ebay.co.uk/itm/144216409673?
If no tap wrench you could try a suitably sized open end or maybe a ring spanner  or multi point socket if your lucky, that suits the square end . You won't need the full advantage of the tap wrench to refinish the thread. You will likely need to use the tapered tap to get a good start on the thread. Dipping the tap in a drop of oil won't go amiss.

Awesome that's the exact thing I've ordered plus a tap wrench. Thanks for the tip on using the tapered end.

[Call the midlife!]

Lol  I must confess... This miiight be the reason I'm in this situation...

Whatever you do, don't listen to my advice, although I'm just about to put mine back on to facilitate getting the engine back in 😂
And I you DO chase the threads out, take your time and keep it straight or you'll end up with the broken half of a tap in the hole.
Not that that's what I've got in my ARB mount hole, honest...

[Joesson]

Awesome that's the exact thing I've ordered plus a tap wrench. Thanks for the tip on using the tapered end.

I'm guessing you have not tapped a hole previously, be aware that when you feel increasing resistance to turning the tap you should back off/ rotate ACW half a turn or so and then go again.

( When  tapping new, particularly small fine threads it is good practice to withdraw the (taper) tap to clean off the swarf produced that could damage the new thread or break the tap).

[MrChris]

I'm guessing you have not tapped a hole previously, be aware that when you feel increasing resistance to turning the tap you should back off/ rotate ACW half a turn or so and then go again.

( When  tapping new, particularly small fine threads it is good practice to withdraw the (taper) tap to clean off the swarf produced that could damage the new thread or break the tap).

I have not tapped before although I've been watching some YouTube videos. Given that these are existing holes sounds like I should just be able to take my time and get them "straight" again, I'll be sure to back off plenty too.

[MrChris]

Just to round this one off (see what I did there?), my tap wrench was too wide to get underneath. So I grabbed the best looking of the 2 bolts I have (still waiting for the new ones from J-SPEC), cleaned it up good and proper and used WD40/machine oil to wind the screw in and out. One thread was fine very quickly after doing this. The other took a lot more persuasion but got there after winding in and backing off over a long period of time. The new bolts will help, but I know now that once I've got them they'll go in no problem.

Thanks everyone who contributed in this thread.

[Ardent]

Drop of oil, impact wrench, senddddddd ittttttt!

Not sure why, but that does make me smile every time I read it.

[Ardent]

Thanks everyone who contributed in this thread.

That's what we do.
J spec sorting you out, so that is that.
But, sometimes just Going to Mr T is the thing to do.
And a dip into the reference section, will give you just about every part number there is.

[J88TEO]

he other took a lot more persuasion but got there after winding in and backing off over a long period of time.

If you cut a groove on the threads this acts like a tap.