Brake Bleeder Screw Size?

Are brake bleeder screws on calipers all the same size? I need to replace the little rubber caps on several (on multiple cars) and want to just order a bunch but, want to make sure they are all the same size (or close). Couldn’t find a straight answer online as most sites referred to length/thread size and I just care about diameter of the top so the little caps will fit/stay on.


I would guess they’d vary from foreign to domestic, but I bet a call to your local Parks store would be your best bet.

5/16ths rubber caps work on most passenger vehicles.

Bigger stuff like trucks use 3/8ths

They are all over the place, but those two size caps will fit most bleeders

EF has been reputed to know stuff… I can’t pull that sort of institutional knowledge out, another reason why CF community is looking good!

instead, i bought a set of relatively inexpensive digital calipers a while back and they have definitely helped me make fewer runs to the hardware store enough to pay for themselves. the top hit on the top shopping website is $22

does everybody know what taper their trailer spindles are? i do now!

God bless a saltwater fisherman.

Thanks for the info.

And yes, I do know what size spindles are on both of my trailers.

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He wasnt talking about the back of the spindle where you measure the ID for the bearing size

he was asking if you know the taper of the spindle.

i think thats what he meant

Yes, I know that as well. Well, not from memory but I wrote it down.

Heigh ho, heigh ho,
to the parts store I go!

I usually punch/pull the old ones out and look at the numbers stamped on the bearing cause my CRS* condition gets worse all the time




Cant Remember Sh%#

I’m accustomed to the kind of catastrophic failure that results in needing new spindles, etc. so I should probably get this stuff tattooed on my arm

This time all I really need is a grease seal, anybody wanna bet on the big boat store having a loose part? Otherwise I’m in for a new hub and the old one becomes a spare that I’ll piece together when I’m next at Seel’s to pay for a big job.

You can get what you need at autozone or advanced auto, I carry a spare hub and floor jack for the inevitable roadside misery

Floor jack is a huge savings in elbow grease.

Speaking of grease, I think the easiest way is to carry a spare with hub already mounted on it, then it’s just 1 cotter pin and castle nut instead of 5 rusty lugs on the side of the road.

After that, you’ll want a couple of these, then you can deal with the damaged tire/rim/hub later

Fortunately I’ve been lucky and ever had any issue with bearings on the road.
But I do once a year remove my bearings and clean them and repack them. Also have buddy bearings.
And whenever we make a pee stop or gas stop I ck the temperature of the bearings.
They’re typically around 95 to 100°.
And of course the axle with the brakes is usually 10 to 15° hotter depending on how hard I’ve been breaking.

I try to keep some disposable rubber gloves to keep my hands soft and supple :rofl: and been told not to do it but I’m hardheaded and I anti-seize my lugs, pulled dual axle trailer and boat over 600 miles just shot grease to wheel bearings every 2 hour pee break. Keep the center console in the middle of the dual axles right OTC?

Yep !!!
And back to the original question. I never really worry about the caps.
Finger a little grease on it.

Yeah, I know, not really necessary but some things I can be a little OCD about.

Inner seal? Any idea on part#? I have four in my truck, and I’m heading to IOP in the morning. Lord knows, I can’t possibly need all four on one trip?

My hubs are six lug, but I think all #41 spindles use the same inner seal?