| Author | Message | ||
     Nick Adlam Frequent User Username: crewes_control Post Number: 57 Registered: 12-2015 |
Evening Gents I'm soon to embark on my annual major "Summer" service, which this year will include replacing the water pump and the two high-pressure ACV to body hydraulic hoses. I've read up on the procedures and they sound straightforward. Apologies if these have been covered elsewhere, but I thought I'd ask for any extra hints Water pump- how difficult are the 6 main screws to remove?. I'm worried about corrosion/seized threads. Any other niggles to worry about?. I'm aware of the 2 countersunk screws. ACV hoses- will fluid start haemorrhaging out from the holes while I'm fumbling around under there?. I don't have the luxury of a hoist. Also, does the G-valve need to be bled?. From memory, there is a nipple there. I'm assuming that it's prudent to bleed every single nipple in the system?. thanks! | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 271 Registered: 10-2010 |
Hi Nick, I didn't have any difficulty with the water pump screws when I did mine. The only fiddly part I can remember is keeping the large o-ring in place when you fit the new pump. (Note: I'd recommend against rebuilding your pump. From my experience, the seals in the rebuild kit are inferior to the new after-market pumps, and not much different in cost.) Can't comment on the hoses. I had Paul do that on my car. ;) Cheers, Jeff. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2070 Registered: 6-2009 |
Nick, If you depressurize the system (which you must, by the way) before you start working on the high pressure ACV hoses you will not get massive amounts of fluid loss when you remove them. You'll always have some. Please read: Flush and Bleed Your Silver Shadow/Bentley T Hydraulics/Brakes the Easy Way Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1417 Registered: 5-2012 |
Nick I would recommend buying some brake hose plugs/caps from you local auto factor to plug the brake pipe when you disconnect it. When I did mine I had a very slow trickle but after a few hours quite a lot of fluid had been lost. Geoff | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2071 Registered: 6-2009 |
Geoff is correct if you want to plug all fluid loss, but you can buy bleed screws to use since they work perfectly well as blanking plugs for this purpose. Unless your reservoir is full of nearly new fluid, I'd use this undertaking as an opportunity to flush the system and empty it (as much as it can be emptied) prior to starting. If you're going to be bleeding the whole system anyway there's no harm in opening all your bleed screws at the calipers, putting a weight on the brake pedal, and running the car until the reservoir is drained (promptly turning the car off as soon as that happens). The concern when bleeding about not allowing the fluid to drop below the top of the reservoir filter screens is that you don't want to introduce air into the system when you're actively trying to get it out. You don't have to worry about this at the end of the flushing process as you'll be purging the system of air during the bleeding process later. I only once succeeded in having the system actually slowly empty itself from the reservoir when I had all the bleed screws open and the motor off. I'm guessing this is probably secondary to how the pump pistons are positioned when you turned the car off. In all other cases I had the pumps assist me with that part of the process. Brian | ||
| Omar M. Shams Grand Master Username: omar Post Number: 824 Registered: 4-2009 |
Dear Jeff, If you ever do the water pump replacement job again dont worry about the o ring. Good ol vaseline will hold it in place whilst you put the pump on. I use vaseline in my garage as a standard tool - and very handy it is too. | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 272 Registered: 10-2010 |
Hi Omar, Yeah, I usually use grease for that sort of thing, but didn't think it was a great idea on the cooling system. Didn't think of Vaseline! Cheers, Jeff. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2072 Registered: 6-2009 |
Well, Vaseline is petroleum jelly, so the same issues that apply with grease can and do apply. That being said, I've soaked EPDM O-rings in oil for months (I've got one that's probably been in its bath for 2 or 3 years now) with no ill effects. In a low-pressure situation, which a cooling system is, I can't imagine that the use of grease or Vaseline is going to have an effect one way or the other. If one wants to be anal retentive you can always pick up silicone plumbers grease and use it instead. It's meant to be used on seals associated with water and water-based fluids. Brian | ||
| Nick Adlam Frequent User Username: crewes_control Post Number: 58 Registered: 12-2015 |
Thanks for the great replies gents- appreciated. I hope to have those hoses done in about 10-mins, so a slow drip is fine. As Brian pointed out, the position of the pumps will decide!. A recond water pump from Flying Spares is on the way. I'd never bother rebuilding mine- not worth the hassles. I'll be using Permatex Aviation form a gasket to hold that pesky o-ring. I assume that stuff is fine on rubber?. I've used it before with good results. | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 41 Registered: 2-2013 |
Wondering if you did in fact use the permatex on the o ring, i've heard this is a no-no, as the O-ring needs to be free to seal itself. But I too have been tempted to use a gasket sealer. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1267 Registered: 5-2015 |
To bleed this section of the hyd system after the ACV hoses have been changed. Start engine allow brake pressure warning lights to go out. Pump brake pedal for about 50 pumps. This will circulate fluid through the ACVs and the brake valves back to reservoir along with any air. The g valve is on the high pressure circuit on both the SY1 and SY2. If the pedal is pressed to fast when bleeding the rear brakes the g valve will block off the fluid to the rear calipers ( one circuit only at the rear calipers ). If this happens just release pedal and go slower next time. To bleed the rest is straight forward. apply brake pedal and open caliper nipples one at a time with engine running take out say 50ml per pair of caliper pistons ( one nipple for each pair of caliper pistons ) full system bleed. 4 nipples front calipers--2 nipples ride height-- rear brakes SY1 2 nipples No2 power circuit (g valve on this circuit)---- master cylinder 2 nipples. rear brakes SY2 4 nipples ( pair of nipples does the g valve as well) The g valve will also lock up if nipple opened too fast or too much. The master circuit has to be pedal pumped like a normal car. SY2 easy to bleed and quick to bleed SY1 has a master which can be a real bitch to bleed. To bleed master circuit bleed through to clean fluid. lock nipple pump pedal so pistons are in position then retract pistons with nipple open. The idea is that any air is driven to the caliper behind the piston and when piston is retracted with nipple open the air goes out through the nipple. Note at all times the pads or levers must be in place the pistons must not come out as far as the disk. | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 42 Registered: 2-2013 |
Any input on the oh ring? To permatex or not to permatex? | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 299 Registered: 10-2010 |
I'd be a little worried using something that sets up. What about hylomar? Cheers, Jeff. | ||
| John Beech Prolific User Username: jbeech Post Number: 179 Registered: 10-2016 |
Ed, A dab of grease (or Vaseline) is SOP for holding o-rings in place for assembly - why risk complications? -- John | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 43 Registered: 2-2013 |
My original Behr radiator began leaking from the header tank so I had Wizard cooling make me a custom aluminum replacement. Although the water pump was not leaking I chose to have it rebuilt while the car was apart anyway. Flying Dutchman pumps in Oregon just sent it back and I am going to install it this weekend. I agree that the o-ring should only need vaseline to hold it in place and help it seat, but when I removed the pump there was a very thin layer of something on the mating surface of the pump. Although very thin, it was quite hard and required considerable scraping to clean the surface which made me wonder if something else was needed for assembly. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1022 Registered: 4-2009 |
Dear Ed, We have taken these pumps out of cars enough times to assure you that the o ring alone is all you need. As long as the o ring is the correct size and thickness - you should not need any gloop of any kind. As John rightly says - vaseline or grease is good to assist with supporting the o ring during assembly. Thanks Omar | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1728 Registered: 6-2006 |
Agree. No sealant is normally necessary. Unless there is severe corrosion on the aluminium housing. I've seen a few where there was so much metal missing that sealing would be marginal. Hylomar was then used as an extra precaution. Antifreeze is important and goes off due to time more than mileage. | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 44 Registered: 2-2013 |
Thanks for the input, there is no pitting whatsoever on the mating surfaces so I will assemble with Vaseline and a new o-ring. | ||
| Nick Adlam Frequent User Username: crewes_control Post Number: 83 Registered: 12-2015 |
Gents Thanks for bringing this up. I used Permatex non-hardening sealant for insurance as I really don't want to repeat this job. My water pump housing was good but the recond pump I bought showed some pitting at the mating surface :/ 4 Months later, all is very well. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1268 Registered: 5-2015 |
RTV gasket in a tube works well with O rings. |
