Bleeder valve size - single circuit

Derek UK · Feb 22nd, 2019, 11:37

Can anyone confirm the sizes of the bleeder valves for the single circuit Amazons and 1800's? Brookhouse shows that the front callipers and rear cylinders have bleeders with different part numbers so maybe they are different sizes too. Possible sizes I have found are 1/4" 28tpi UNF and 3/8" 24tpi UNF. They are not likely to be bet metric although metric size bleeders are common.
Reason for asking is I was looking at Goodrich Speed Bleeders and sizes are listed but not which ones fit which cars. Maybe someone here has fitted a set?

Army · Feb 22nd, 2019, 13:56

I've just ordered some new single circuit calipers from VP that should arrive today

If not I'll look at the old ones I have at the workshop tomorrow (so long as no body else posts the answer in the mean time)

Derek UK · Feb 22nd, 2019, 15:54

Thanks. Enquiries are ongoing. A contact in the USA rang the Speed Bleeder company help desk and they gave him their number for the 1800 ES (callipers front and rear). ES's use their SB1428 which is a 1/4" 28 pitch bleeder.
They didn't have a number for the single circuit cars. I have sent an enquiry to Simon at Brookhouse.
I have just used a vernier on a 3 piston single circuit calliper bleeder and it measured 0.395" which is about 0.020" bigger than 3/8" so maybe that is what it is. 3/8" 24tpi UNF.

Army · Feb 23rd, 2019, 15:11

Ummm not exactly how I expected things to go.

Can't find the calipers

Can't find the original bleed screws

New single circuit calipers from VP are in Germany (apparently) - still on their way

I did find some new caliper bleed screws that I ordered previously from VP (when I was hoping the calipers that came with the car could be saved)

Part number => 656455

Couldn't find my proper trustworthy pitch gauge either - one of those days!
Had to use this Gunson thing - I'm not a fan of Gunson so I made the pictures to show what I could see...

Pitch looks like it is 24tpi

3/8" diameter

I hope this helps a bit.

I'll have another look for the calipers tomorrow and the original bleed screws and compare if I find them

Derek UK · Feb 23rd, 2019, 19:56

That's looking pretty positive at 3/8" by 24tpi which is the other size I posted. Spanner size looks to be 3/8" too. #656455 are the ones listed for rear cylinders whereas the part for the single circuit callipers is #664823. Thread size might be the same but longer, or shorter. Goodrich shows 3 different lengths for this size so that might account for the different part number. Because the bleeder has to go through the brake back plate they probably need to be longer and that extra length allows easier access with a spanner. The calliper ones are out in the breeze and easy to get a spanner on.
Thanks for the pics and info.

Army · Mar 5th, 2019, 19:43

The calipers have arrived and I've gotten round to making pictures of the new bleed screws

Same threads as the other ones

Feb 22nd, 2019, 11:37	#1
Derek UK VOC Member Last Online: Today 23:46 Join Date: Jul 2006 Location: Chatham	Bleeder valve size - single circuit Can anyone confirm the sizes of the bleeder valves for the single circuit Amazons and 1800's? Brookhouse shows that the front callipers and rear cylinders have bleeders with different part numbers so maybe they are different sizes too. Possible sizes I have found are 1/4" 28tpi UNF and 3/8" 24tpi UNF. They are not likely to be bet metric although metric size bleeders are common. Reason for asking is I was looking at Goodrich Speed Bleeders and sizes are listed but not which ones fit which cars. Maybe someone here has fitted a set?

Feb 22nd, 2019, 13:56	#2
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	I've just ordered some new single circuit calipers from VP that should arrive today If not I'll look at the old ones I have at the workshop tomorrow (so long as no body else posts the answer in the mean time) __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Feb 23rd, 2019, 15:11	#4
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	Here's what I could find today Ummm not exactly how I expected things to go. Can't find the calipers Can't find the original bleed screws New single circuit calipers from VP are in Germany (apparently) - still on their way I did find some new caliper bleed screws that I ordered previously from VP (when I was hoping the calipers that came with the car could be saved) Part number => 656455 Couldn't find my proper trustworthy pitch gauge either - one of those days! Had to use this Gunson thing - I'm not a fan of Gunson so I made the pictures to show what I could see... Pitch looks like it is 24tpi 3/8" diameter I hope this helps a bit. I'll have another look for the calipers tomorrow and the original bleed screws and compare if I find them __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Feb 23rd, 2019, 19:56	#5
Derek UK VOC Member Last Online: Today 23:46 Join Date: Jul 2006 Location: Chatham	That's looking pretty positive at 3/8" by 24tpi which is the other size I posted. Spanner size looks to be 3/8" too. #656455 are the ones listed for rear cylinders whereas the part for the single circuit callipers is #664823. Thread size might be the same but longer, or shorter. Goodrich shows 3 different lengths for this size so that might account for the different part number. Because the bleeder has to go through the brake back plate they probably need to be longer and that extra length allows easier access with a spanner. The calliper ones are out in the breeze and easy to get a spanner on. Thanks for the pics and info. Last edited by Derek UK; Feb 23rd, 2019 at 20:01.

Feb 22nd, 2019, 15:54	#3
Derek UK VOC Member Last Online: Today 23:46 Join Date: Jul 2006 Location: Chatham	Thanks. Enquiries are ongoing. A contact in the USA rang the Speed Bleeder company help desk and they gave him their number for the 1800 ES (callipers front and rear). ES's use their SB1428 which is a 1/4" 28 pitch bleeder. They didn't have a number for the single circuit cars. I have sent an enquiry to Simon at Brookhouse. I have just used a vernier on a 3 piston single circuit calliper bleeder and it measured 0.395" which is about 0.020" bigger than 3/8" so maybe that is what it is. 3/8" 24tpi UNF.

Mar 5th, 2019, 19:43	#6
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	Finally got 'em The calipers have arrived and I've gotten round to making pictures of the new bleed screws Same threads as the other ones __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

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