Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Dave69 on July 04, 2010, 12:36:47 PM

Title: bolt size thread
Post by: Dave69 on July 04, 2010, 12:36:47 PM

anyone know the thread size for the bolts that hold the rear wheel brake cylinders on the back plate. these are fitted to the mk1 cherokee but the cyclinders are universal

they are a coarse imperial thread, and short in length.

any ideas

Title: Re: bolt size thread
Post by: Panic mechanic! on July 04, 2010, 02:57:17 PM

bubba will know, but i am shocked you don't dave. :017:

Title: Re: bolt size thread
Post by: Bubba on July 04, 2010, 07:19:52 PM

i dont with out having one to look at i just keep all my imp bolts so that i dont need to fret over replacements

Title: Re: bolt size thread
Post by: Dave69 on July 04, 2010, 07:57:04 PM

part number appears to be 6028 921

Title: Re: bolt size thread
Post by: Nosebolt on July 04, 2010, 08:05:07 PM

does this help (http://mdmetric.com/tech/tict.htm)

Title: Re: bolt size thread
Post by: Dave69 on July 04, 2010, 10:07:26 PM

it's a start thanks Bruce

Title: Re: bolt size thread
Post by: PtP on July 05, 2010, 07:17:57 PM

Quote from: Dave69 on July 04, 2010, 12:36:47 PM

anyone know the thread size for the bolts that hold the rear wheel brake cylinders on the back plate................

I’ve just found an old pair of cylinders from my ’97 TJ and the threads are ¼-20 which is the US equivalent to our M6.

¼-20 is a nominal ¼” diameter bolt with 20 teeth per inch. Don’t use M6.

I have 4 spare bolts which are about 1” long if you’re stuck. :icon_biggrin: You can always cut them down to length.

Title: Re: bolt size thread
Post by: eastryjeep on July 05, 2010, 08:47:39 PM

0.25" Dia x 20 TPI is probably one of the following, but they are NOT interchangeable:
1/4" Whitworth (BSW - 55 degree pitch and a British Standard) or more lilely;
1/4" Unified Coarse (UNC - 60 degree pitch and an American standard);

With regards the length, a hacksaw is a great adjustment tool but make sure to deburr the end.

Please make sure you get a good grade bolt as your life does rather depend on it in this case!

As a general rule of thumb Allen/socket screws are a higher grade steel than your average bolt, so if in doubt fit a socket screw if you can't find the real McCoy but be careful about Stainless steel fasteners in cast iron/steel parts, they may mot mix as well as anticipated!

Please remember these are safety items - and that my rule of thumb in no way makes me liable for anyone's longevity!

Title: Re: bolt size thread
Post by: Dave69 on July 05, 2010, 09:43:56 PM

unc is the thread even though the bsw will fit also but it is loose so tha is a no-no

just need to cut the cap heads down to size don't know the actual size as it was in a box of old spare parts i had


thanks for all the help