Part 8: Two Steps Forward, Three Steps Back
Expecting the unexpected
There are times when working on a project where things don't always go entirely to plan. Sometimes this is down to human error, like when we trapped the vacuum hose under the cam ladder, or when I was using an angle grinder to vent my frustration on a sheared off subframe mounting bolt and promptly cut through another vacuum hose in the engine bay. That's when Captain Cock-up comes out to play. No idea why he enjoys inflicting terminal damage on vacuum hoses in particular though, may be that's “just his thing”. Sometimes plans are derailed because someone in the Longbridge design office gave little consideration to us little people 15 years down the line when we come to taking their carefully crafted designs apart following many years of exposure to The Great British Weather and local council traffic departments' salt laying antics; subframe bolts that simply shear off because they're corrosion-wasted at their neck where they pass though their mounting holes in the subframe brackets (excellent moisture collection points), meaning you can't apply adequate torque to remove them without first snapping them.
And then, there is tin worm. Not bodywork tin-worm – although the 'Shed had plenty of that in the non-structural front wings as we've already seen. No, the central tub of this MGF remains largely and surprisingly rust-free after over a decade of even major neglect; the underside of the 'Shed remains remarkably pristine, with just the merest suggestion of surface rust here and there at the end of some of the seams. Bodywork protection, over all, appears excellent. It is a shame therefore that similar levels of fastidious attention had not been lavished on the subframes, which appear to be stuck in a 1960/70s BMC/BL time warp. We've already seen some horrific rot on the rear subframe that came from the donor car. That ultimately kyboshed the simple yet cunning plan of unbolting subframe and engine as a single unit, wheeling it under the 'Shed and bolting it up – a task that might only have taken a day. But no, terminal subframe rust lead to many days/weeks/months delay, as we've already read about.
The Shed's original rear subframe had plenty of surface rust, yet in the main appeared solid, but in spite of its apparent health it was ultimately replaced by the Ebay bargain replacement because this was a cheaper option than replacing the missing engine mounting member from the X-part catalogue. But given that it wasn't “too bad” I figured that the front subframe should be okay; it has experienced the same environment as the rear for the whole of its “life” after all. Same environment in all regards except for one: no oil leakage from the engine/transmission. Perhaps I should have been more suspicious of the front subframe's condition, particularly as there is no oil to be spilt upon and preserve the metal in greasy residue. Even so, it looked absolutely fine, other than the expected surface corrosion, from the initial visual inspections underneath when it was still bolted up on the car.
At the end of the last instalment, I had a car that looked like an MGF again – and it was on four wheels. At the end of this instalment, dear reader, I am sorry to report that the 'Shed, once more, is back on two wheels and a pair of axle stands. Arrrrgggghhhhh! Here's the story of how things went badly backwards...
We need a clutch!
For regular readers with good memory (there will be a test at the MGF Register's annual Christmas Natter! Ha ha ha), the last report ended with Project Shed triumphantly back on four wheels (albeit on its bump-stops, as the Hydragas suspension had yet to be re-pressurised), but with the clutch hydraulic pipe dragging on the ground. Why is this, I hear you ask? Well, it appears that the whole car is built around the clutch and brake hydraulic pipes – they must be one of the first components to be fitted on the production line, and everything else gets fitted around them. Including the front subframe. The original clutch pipe on the 'Shed had been sheared off as it entered the engine bay – a victim of the process of having its engine and transmission removed by its last owner for a radical Mini-based project.
In other words, the clutch pipe needed replacing.
I had a suitable replacement from the donor car – albeit one that necessitated a swap of the clutch master cylinder, but this is easily done. Removing the old, damaged clutch pipe was easy, using plenty of brute force and ignorance; I don't need to reuse this pipe after all – it's scrap. But fitting the new one proved impossible with the front subframe in place, despite many attempts at jiggling it through available gaps. It's a non-starter. The front subframe has to come out before replacing the clutch pipe.
Not a problem – not least because I wanted to replace the existing standard rubber subframe mounts with those nice solid TF items that I'd already managed to purchase. And anyway, the front suspension needs rebuilding with nice new Poly Urethane (PU) bushes. So, given the that the 'Shed's back end had been largely rebuilt, pending a suspension rebuild with PU bushes, I thought that the next job would be to get the front subframe off the car, repaint it, and fit the clutch pipe at both ends – re-establishing a now long-lost connection between master and slave cylinders. Thereafter, the subframe could be raised back into the car and bolted in on those aforementioned solid TF subframe mounts. Job done.
The best laid plans...
Of course, dropping the front subframe would mean undoing the subframe mounting bolts. I have to say, this was not a task I was looking forward to, not least because the last time I tackled this (fortunately on the donor car, so it didn't matter so much), I managed to shear off four of the six bolt heads. I should change my name to Alan Shearer (sic). Ho ho ho – see what I did there? Ahem, let's move on.
So on this occasion I thought I'd share the blame with Tim Woolcott – he tacked the nearside and I the offside. Former Newcastle striker, Alan Shearer is well aware of the offside rule, and I, his new namesake, played it to its automotive best and managed to remove all three offside bolts without too much trouble (technique: nip the bolt up a bit to crack off any stiction/corrosion, then undo).
Tim however, wasn't having quite so much luck on the nearside. A 100% failure rate. Utterances of an 'F' word that rhymes with “luck”. It must be said that Tim went a little “Gordon Ramsay” on us. I didn't feel too bad about it though – mainly because I didn't do it. Perhaps also due to feeling what our German friends call “schadenfreude,” which roughly translates as “delighting in other's misfortune” - except that here, Tim's misfortune was also very much my own.
I suspect that the best approach to this problem would have been with the use of an oxyacetylene torch to bring some warmth to the proceedings. Nothing quite like heating a lump of stubborn metal up to a cherry redness to satisfy the cockles of your heart (and most likely, burn off quite a lot of frustration!). Now whilst my tool kit is reasonably well equipped, it doesn't extend to this kind of equipment, and I doubt that my in-laws would be that happy with the idea of gas cylinders sitting inside their garage along with parts of MGF... Anyway, too late now to worry about that and thoughts of “we should have visited the local tool hire shop before starting this job” were banished: we'll have to come around to sorting out these little blighters in due course – including the other sheared off bolt in the rear subframe mounting that we inherited when we collected the 'Shed from the South Coast all those many months ago...
Subframe away, and ... oh dear ...
With brake pipes disconnected (these are to be replaced with Goodrich braided items, purchased on-line), the steering column disconnected (a bit sad – connecting it up was one of the first reassembly tasks undertaken on the car and therefore rather symbolic!), the front subframe can be dropped out of the way, leaving a nice clear field of view to re-route the clutch hydraulic pipe. This it did. And it also gave us a chance to inspect hitherto un-observed aspects of this subframe previously hidden under the front bodywork.
As with the corrosion in the donor car's rear subframe, it was Tim (again! Is he some kind of rust jinx?) who spotted the problem with our freshly 'liberated' front subframe. As any pub-quiz aficionado will tell you, the front and rear subframes on an MGF are the same – but there are obviously differences that suit their application in the front and back of the car, not least because the rear subframe has to carry the engine and the front the steering gear. The front subframe, in place of the engine carrier, has two longitudinal rectangular section channelled steels that ties the front and rear of the subframe together, presumably to aid in longitudinal stiffness of the assembly and perhaps also has some role to play in the car's frontal crash structure.
It was with these two box section “Longitudinals” (part number KGK100500, if you must know) where the problems lay. Both had cracked clean through just ahead of the rear mounting bolt. Both displayed rather a lot of surface corrosion, but I don't think that this superficial rot played a pivotal role in these components' failure. Nor was crash damage – there are no tell-tale ripples to be found or any distortions in evidence. Initially, I thought that the failure looked like a fatigue failure, but this is not my field of expertise. But on further inspection, it appears that corrosion has crept between steel where it is double skinned and eaten through. But I wonder whether metal stress might have contributed: I'd certainly like to know, so if anyone (any metallurgists/ structural engineers out there?) can help, I'd be very interested in finding out if the theory is correct. More to the point, if it has failed on what I presume is a relatively low-mileage MGF (true mileage unknown), are there other cars out there harbouring similar problems of which their owners are blissfully unaware?
The solution to the problem of the longitudinals' failure is one of two options: repair or replace. I can't weld (want to learn though), so repair not straightforward (for me anyway) – and besides, if riddled with metal fatigue and rot, is repair desirable? No, I didn't think so. Replacement with a solid second hand subframe is therefore on the cards. It is tempting to buy a motor-sport front subframe that benefits from being seam welded and therefore stiffer for better suspension geometry control under cornering, but their prices, even second hand on the Bay of E is not very attractive to my PayPal account, thank you. So at the moment is the hunt is on, and I'll let you know how I get on with this next time.
At least we can get one job done!
But one shard to good news; removal of the subframe finally meant that Tim and I could at last get on and fit the clutch pipe! I had roughly put the pipe in broadly the right place already when Andy Phillips and I were getting the 'Shed ready for its (non) attendance at MGFest 09. With the front subframe now wheeled away and parked in a corner of the drive in disgrace, the master cylinder end of the pipe could now be mated up. This went well, although a little judicious bending was required here and there, simply because the pipe while in storage had become a little distorted in amongst all the rubbish... er, no, I don't mean that, er, I mean valuable MGF spare parts.
With that end done, time to follow the pipe along its length, pushing it into the under body fasteners until we got to the point where we needed to ensure that the pipe reached the clutch slave cylinder. This was more a question of making sure we had the pipe threaded the right way past all the major suspension/ transmission/ engine components. Fortunately, with my and Tim's MGFs on hand, there were no shortage of cars to look at to work out how the pipe should run to the clutch slave cylinder. Again, a little bit of persuasion here and there got the pipe into the right place and the union nipped up. The clutch hydraulic system now needs filling and bleeding – which should be straightforward enough, but is currently on the seemingly infinite and expanding “to do” list.
And then there's still that dratted front subframe to sort out...!
Good news masquerading as bad
Whilst replacing the clutch pipe has proven to be one of those jobs that one
wishes one didn't have to do, and is a whole load more involved than is perhaps
ideal because of the need to remove the subframe, in a way I think that I am
happy that we did. I certainly don't relish the task of removing the sheared
bolts resulting from the subframe's removal, and the discovery that both the
Longitudinal steel box sections had cracked into two was rather, how shall we
say, “disappointing,” but better find that out now and be in a situation where
the problem can be rectified. It's a strange, curved ball that has been served
to us – but at least there is a silver lining to this gloom cloud of bad news.
When rebuilt, the front end of the 'Shed will be in far better condition, and
more rigid, than the condition we found it in. And that, surely, is good news?