Bleed nipple screw on Princess caliper

[TR Tony]

Bit of an obscure question for anyone who has knowledge of using the Princess 4 pot caliper with vented discs on the TR7!

There seem to be 2 types of bleed screw. On the calipers I have got the bleed screw in the top position on one side has a small head (the bit where the fluid actually comes out), the other side has a fatter head. Also, both sides do not screw right down into the caliper, but sit a little proud with some thread showing under the hex head.

These screws were in the calipers when I got them, and I don't have any leaks but I wondered if they are the right screws? Should they sit proud of the caliper body? Anyone out there got any expertise on they could share with me?

Tony

<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">

[Stevie P]

Same set up as on my car.

I recall back in the day when I put these callipers onto Escorts, there was a mod in plumbing one top bleed nipple to to one of the side holes (where you have a hex bolt), this was was the second hose used to come into the calliper.

both sides of the calliper used to work fairly independently!

There was a mod, where I think the passage way between the halfs was opened out and only on inlet used, the other blanked, and both bleed nipples left in place.

I think that's correct and hope it makes sense.

Steve

[sonscar]

Here are some poor pictures of the calipers on my car.infuriatingly they miss out all the important detail.



Hope they help.steve..P.S they only have one feed pipe and 4 bleed nipples.I rebuilt them with stainless pistons and seals from BIGRED.The threads should be visible as the nipples seat on a taper at the bottom of the hole.If no threads were visible the taper might or might not be seated.

[dursleyman]

I have mine set up a little different as I have made an internal drilling in the caliper. The single feed is still at the top like on a standard Princess but it doesn't need the external link pipe. You can get various lengths of bleed nipples so it might be you have different lengths fitted?





Russ

1980 TR7 Sprint DHC, 1981 TR7 Sprint DHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

[img]http://i1040.photobucket.com/albums/b410/dursleyman/TR7%20web%20picture/IMG_0479-Optimized.jpg[img]

[TR Tony]

Thanks both, and I take the point about the screws going down far enough to sit in the tapered seat.

My reason for asking is that I am trying to put the original 13" alloys back on the car. With a 3mm spacer one side clears the caliper (just!) but on the other side the top of the bleed screw (the one with the fatter head) catches the rib on the inside face of the wheel. So I wondered if I could use a slightly shorter bleed screw, or if I could find another screw with the small head to match the other side. I would like to keep the vented disc set up if I can as it does work well.

Tony

<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">

[dursleyman]

Tony, I bought the whole kit off Ebay for £50, they came off a TR7 rally car that was being broken.
If you look at the first of my pictures you will see that the mounting lugs have been filled and re-drilled so the calipers sit slightly closer to the hub and will fit under 13" wheels - just. I did the internal drilling thing myself because I hate that external link pipe that people use.

[sonscar]

Mine has no external link pipe but I do not know what has been done to them as they were fitted when the car was bought.The lugs have not been redrilled and the discs are 254mm dia,22mm thick vented.They fit under the K and N Starmags of unknown vintage without spacers.Steve..

[john 215]

Hi

My old Princess calliper's have a three way valve, the flex hose splits and a double feed pipes then enter the calliper. I am sure each pipe then feeds a pair of pistons, one each side.

The holes have also been filled and re-drilled to move the calliper closer to the disc ( standard TR8 ) will ( if I remember [:o)] ) get some pictures later. I am I got them from Rimmers at least 20 years ago.

Cheers John




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[TR Tony]

Thanks everyone for the comments & pictures. Russ - my set up is like yours. In your bottom photo, the bleed screw on the left of the caliper (nearest the wheel) is the one that I find catches on the inside of the wheel on one side, whereas the other side has a different screw in that does not catch.

As you say, maybe it is just a shorter screw that provides those few millimetres of clearance.

Tony

<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">