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MG MGB Technical - Brake pipe route

I'm part way through a winter rebuild and I've just finished replacing and re-routing the brake pipes. I've run the pipes to the servo along the top of the scuttle above the heater and behind the bonnet hinges (see image). Today I spoke to my neighbour who related the story of many years ago he had a BGT and while driving, the bonnet came open and wrapped itself over the roof. This got me thinking that in the unlikely (I hope) event that this happened to me the hinges would probably crush the pipes. I'd then be in situation of not being able to see or stop. I'm thinking about re-routing them so they aren't behind the hinges. Before I do this I'd value other opinions on whether I'm being overly paranoid and should I bother with this.

Bob


R.A Davis

I have to admit that the flying bonnet scenario was the first thing that occurred to me when I saw the routing.
Dave O'Neill 2

Best way is along the front of the heater box.


Ste Brown

Actually gentlemen, the fying bonnet actually happened to the GT I have! It was not in my possesion at the time but I still see evidence of the event, not nice! If one was going at speed and the wind was against you, I could see the whole bonnet being torn off. As it happend it tore the bonnet support right off but the hidges held. Anything in between the hinges and body could have been easily cut? That is why I am going to put a couple of leather security straps like you see on the racing MG's. Perhaps some 'rottwieler' leather collars, What are your thoughts. Mike
J.M. Doust

Slightly o/t but its worth, on any car, oiling the bonnet retaining pin regularly and checking its free in its guide. Also it should be adjusted so the bonnet is held nicely aligned and against its stops, but with the pin having movement up and down. This means any loads on the lock are transmited through the spring and the bonnet cant be shocked open. No personal experience but I read about a midget owner having problems and attempting to solve them by adjusting the catch so the bonnet was clamped down harder. This made things worse. When it was re-adjusted to allow for flex both ways it stayed in place. Also check the safety catch regularly, I put a squirt of oil on all moving parts there as well. Oh, and on the release cable as well to ensure that doesnt put any force on the release mechanism, other than when you pull it inside the car. All safety critical items.
Stan Best

Bob, I wouldn't want my brake pipes inside the hinges like that. I have done what Ste recommends, along the front of the heater box.
Mike Howlett

Bob, Route the brake pipes at the bottom of the heater box as previously said,you will find this much easier when you come to bleed the brakes, as the pipes will be lower than the M/C Bill
wm griffiths

Thanks so far for all the advice. My reason for replacing the pipes is the PO fitted a servo and although it was working, and passed MOTs, it was a complete mess. The pipes went along the front of the heater and were tie wrapped to what is, I assume, a heat shield/protection for the fuel pipe that takes this route. As part of the rebuild I've overhauled the heater, when I tried to remove it, it put up a real fight, caused by the foam seal having turned to concrete. In order to get it out I had to use 2 levers one on either side, this was made more difficult by the brake pipes being in the way.

Whilst visiting the club shop I noticed the very nice V8 they had on display had them run above the heater. This looked a much neater arrangement than my mine and keeps the pipes out of the way. I don't have a problem with originality as the car wouldn't have had a servo from new. I've also run the pipe for the nearside front straight from the servo, that way should I need to remove the cross member I can do so without disturbing the pipe work.

I'll definitely be moving these pipes, watch this space, besides, it'll give me more practice with the flaring tool.

As an aside, because of the difficulty getting the heater in and out I'd considered modifying it. I'd thought about cutting the lower part of the front plate off (the bit that sits below the mounting bracket) and welding it to main box. This would then allow the front plate to be removed by springing the clips and undoing 3 screws. I'm not sure if you'd be able to get the heater matrix in and out, I think you would. I haven't done this as I haven't got a spare box and I'm on a tight schedule to get the car finished.

Bob
R.A Davis

I believe Chris Betson (Octarine Services) has done something similar to the heater to enable the front to come off in situ.
Mike Howlett

I concur with those that moved the pipes. All too risky above the heater and behind the hinges. I've gone with the 'front of heater' route and accept that removing the heater will be even more horrible a job than it is already.


Richard Coombs

Doesn't modifying the heater box void the warranty? Seriously, even though the possibility of the hood coming loose is unlikely, it happened to a friend of mine while he and his brother were driving on a highway at 70 mph. The aluminum hood hit both of them in the head, and while they weren't injured, the driver had a hell of a time bringing the car to a safe stop. I have a supercharger kit installed on my '67 and I have the throttle cable routed under the hinge just as your brake line is. The instructions, that came with the kit, said that this was the best way to route it. Now, I'm wondering about that. RAY
rjm RAY

A very neat job Richard, but why did you put the brake pipes on top of the heater shelf? That just makes things awkward. If you run them along the front edge supported by clips they aren't in the way at all. See Ste's photo above.
Mike Howlett

To be honest I thought about the route for ages but never considered forward of the front edge as very viable. As you were kind enough to say my chosen layout has come out looking neat enough. I shall regret saying this but I never intend to remove the heater again so 'awkward'doesn't matter too much.....yet!
Richard Coombs

This thread was discussed between 20/02/2011 and 22/02/2011

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