Post Number: 231
|Posted on Tuesday, 05 February, 2013 - 02:15: |
I'm just curious as to the opinions of the cohort as to the utility/appropriateness of this "new" type of bleed screw that has an internal check valve to prevent "sucking air" for our cars.
On a certain level it seems like they're a good idea simply because they prevent any backward flow. Fluid comes out, but nothing can be sucked back in.
On the other hand, given the way the brake/hydraulic system works on the SY/SZ cars at least, it also seems like it may be overkill.
I'm considering replacing the entire set of bleed screws on SRH33576 and would like some input on that. By the way, does anyone other than Crewe Original still make 3/8-24 bleed screws with a 7/16" head on them? Virtually all that I see available anywhere have a 3/8" head on them.
Brian, who's got one replacement bleed screw on that car already with a 3/8" head and would like for things to be consistent so only one wrench is needed when crawling around "down there"
Post Number: 1204
|Posted on Tuesday, 05 February, 2013 - 06:24: |
Brian, I would only consider the use of check valve bleed screws if they were permanently capped between bleeding.
My concern would be "freezing" or blockage of the check valve due to crud lodgement in the orifice and/or corrosion of the check valve components from road water spray/de-icing salt rendering them ineffective.
One of those items which appear useful but found to be impractical with experience??????? There is a long list of automotive devices marketed over the years which merely removed money from the owner's pocket without any long-term benefit and I suspect this product will be another addition to this list.
Post Number: 76
|Posted on Tuesday, 05 February, 2013 - 06:46: |
Also, on a Rolls there should never be any backward flow. I can't think of any scenario in which that would happen as pressure from the accumulators, which forces the fluid through the bleed screw, is continuous. This contrasts with a conventional brake system where the foot pedal has to be pumped and where on the upward stroke of the pedal air can be sucked into the system.
Post Number: 29
|Posted on Tuesday, 05 February, 2013 - 09:00: |
If the bleed screws are not easily available these days I will machine some up foc for Forum Members with pleasure . We have made a few different bleed screws and it would not be a very time consuming job on the right type of CNC machine . As we are in the UK maybe somebody in Australia could handle local postage /distribution to people ?