Prop rod and heater tube

[Gary Schulz]

I finally got this beautiful new fresh air heater hose installed (thanks Gordon!) and I have found that the bonnet prop rod interferes with the heater trunk. It is not really even close to fitting when I close the bonnet.

What do people do to make the prop rod and heater trunk live together inside the engine bay?

I would say that the prop rod causes my bonnet to stay open by around an inch on that side because of the interference. Do you just squeeze the heater trunk into a more favorable shape by flattening it?

20200523_103422.jpg

[roymck]

Could it be you brake pipes to and from servo holding the hose up too high ?

[Oneball]

I’m not sure if it’s the angle of the photo but the fresh air hose looks like it’s sitting really high.

As Roymck says, is it sitting on something?

[Gary Schulz]

No the brake pipes go well under the hose. It hits at the vacuum chamber for the servo mainly

[Gary Schulz]

My prop rod is perfectly straight. Should it have a kink in it? I think I have others that have kinks... It is very possible this rod was from another bonnet.

[Dearg1275]

Take the bonnet prop off and see if the bonnet shuts properly. They do normally have a kink to follow the contours of the bonnet to some extent.

It may also be why the air hose reducers were introduced to get round the servo. The early Ss had the hose finish at the bulkhead bracket. What year is your car. My USA export 1275 had the hose finish at the bulkhead cross member.

D

[iain1967s]

You could try with the vacuum hose over the top of the fresh air trunking instead of below, to see if that gives a bit more clearance.

There isn’t much room here at the best of times, which is why they changed to the reducer trunking setup on later mk1’s.

But comparing against this photo, I’d agree the brake lines look to be too far over towards the wing, resulting that there isn’t enough ‘drop’ between the reinforcer triangle and the master cylinders.

[Dearg1275]

Here is a photo from the main site that might help. The servo hose goes much deeper and is retained by a P clip on the rear of the servo (from memory).

C12EA5E9-320A-4201-8EA6-CF5C271D6A70.jpeg

D

[Gary Schulz]

Interesting that the servo hose is retained by a P clip. I wasn't aware of that. The brake pipes are definitely not the problem. That last picture is the way my brake pipes are routed which I am pretty sure are correct for my car (June 1964 build). The trunk is being propped up by the servo vacuum chamber and the heater tap. There is clearance between the brake pipes and the trunk and the rod pushes down in the area of the servo.

I think it can't have a straight prop rod. I am almost certain I have seen others that are formed to follow the contour of the bonnet to some extent but it would be nice to confirm.

That last picture is the way my brake pipes are routed which I am pretty sure are correct for my car (June 1964 build). The pipes are supposed to be clamped to the inside wing as in the photo. At least I hope so. I spent a ton of time reviewing pictures of "original" cars in an effort to get that correct! The bonnet closes just fine without the prop rod.

[iain1967s]

You could also try as a test flipping the rubber prop block around so it sticks out the left instead of right - it’s only held on with two pins. If the clearance problem is solved then, you’ll know a bend in the prop is probably going to help.

[360gts]

Gary, notice a few things here that could help with your problem.

1 As already stated...vacuum hose is supposed to help onto the back of the servo with a P clamp. That hose should be at least 23 inches long...

2. The brakes pipes just don't look right! Yes, they should be connected to the inner wing...but they should run across ….then a right angle bend
down,....across again and then straight up to the master cylinder.

3. The vent hose should be held in place by a large clip that is attached to the flitch brace.

Finally, the bonnet prop should have a bend in it..
1 and 2 will help pull the vent pipe downwards.

[Andrew1967]

Here's a pic of the engine bay of my 'S'

Whilst the pipes may not be totally correct, although they seem the same as the example Iain posted up, you can see the brake to servo pipe does run lower down under the hose before coming up to the cylinder. However, you confirm the pipes are not the issue.

Is the servo mounted in the original factory holes and the correct rear bracket used ?

My fresh air hose is from the late great John Kelly but Gordon's are made to the same specification.

I also have the straight bonnet prop fitted, correct for an early car.

[Andrew1967]

Looking again Gary, does the hose pass slightly by the side of the regulator or sit directly on top of it ?

That would make a big difference.

[Gary Schulz]

Heater trunk runs to the side of the regulator. I just measured 1/2" of clearance between the brake pipes and the trunk so the brake pipes are run as per Dearg1275's picture which I believe is correct for my car. Probably much easier to tell how the pipes are run without that heater trunk in there. It is hitting where the trunk runs above and to the right of the servo vacuum housing. It looks to me like there are two different prop rods and I suspect the bent one was to clear the heater trunk on the early cars and the blower motor on even earlier cars than that. It seems that the prop rod in Dearg's picture also has the kinks in it. I found one in my stash and it clears everything. It sorta seems like the OD on this new heater trunk is a little large but it is very nicely made for sure...

I also now have the large P clip attached to the brace and the vacuum hose is very pliable and soft so neither of those is causing an issue however I will attach it per your recommendation.

The one on top seems to work fine...

20200523_152556.jpg

[Catmint]

Hi Gary

I think it may be the regulator that is also causing the problem, there is bugger all room there and this does cause a problem. You may have to squeeze the hose a bit to get it to sit over this. If you look at the photo David posted, the shadowing of the hose looks like it could have been squeezed in here as well and the P clip keeps it in place

(Andrew, if it was from JK, then I made it as well )

Gordon

[Andrew1967]

Well it’s stood the test of time Gordon, 14 years fitted in the car and it’s still like new

I didn’t need to pinch the hose and had no bonnet closing issues with the straight bonnet prop, which I think is correct for a 64 car. Will check AKD3510 when I get home from work.

[whistler]

You can use a smaller diameter hose for the fresh air, utilising a reducer close to the bulkhead. I've seen this done previously a long time ago. Not sure if it was an 'S' mod offered by BMC when optional servo was fitted.

[Gary Schulz]

Well for now the problem is sorted with the use of the kinked prop rod. That kinked prop rod was from an early 997 Cooper so it predates my 64 car. I am not sure if there was a firm switchover date for that. I know it was from this older Cooper because the rod is painted Surf Blue and that was the only Surf Blue car I ever dismantled for parts (wish I still had that car looking back 30 years later!)...

I appreciate all the observations but the prop rod is not touching anywhere near the regulator or the brake lines and the trunk seems to fit in those areas reasonably well. It is only touching (because it leaves a crease) just forward of the servo vacuum housing. That appears to be the area where the kink in the other rod allows for more clearance. By the way, the servo holes in the panel were original since that panel was never replaced, and those holes matched up with the template 1071Bob supplies with his servo brackets. The brackets are both new because I could never locate the old ones but the brackets appear to be perfect in every way in terms of fit etc...

[Andrew1967]

Just checked AKD3510 and the prop does appear to be the cranked type.

Guess I was lucky to get a straight one to work ... must change it before the bonnet prop police arrest me

Glad you have sorted it out Gary

[Gary Schulz]

Thanks for the help Andrew!