King pins swivel axle and bushes

I bought the MGB as a usable, running, legal and roadworthy car. Well its running (just) and legal, but that last one does stretch the trade descriptions act a little. Anyway this means I'm going to have to do more work on it than I had envisaged. One complication though is that for various reasons; largely to avoid annoying the residents, I have agreed not to put any more dead and immovable cars on my drive. This means that anything I do on this car has to be done in one day- drive-in and drive-out. Bit of a problem for me as I tend to work very slowly....

I don't think there is any way I can strip the stub axles, remove kingpin bushes, clean, renovate and refit with new wheel bearings in a single day. Even more so as domestic taxi arrangements often shorten my time available anyway! The solution is to use exchange units... but (glutton for punishment) I don't really want to do that, I wouldn't learn as much about the car, so I would like to do this myself. The solution to my mind was to buy two used stub axles  and a single hub (Andy Jennings MG Spares) so I can recondition them- effectively to prepare my own "exchange unit" before fitting it to the car. This is really a learning curve-it keeps me off the streets (?) but I'm not going to pretend its cheaper- in fact many king pin kits are more expensive than the exchange parts from MGOC - and that's my fallback position if this all goes pear-shaped! However, this approach means that I will be experienced and tooled up for this particular job ... and although this is my first kingpin swap in an MGB, its actually my fourth overall so its probably now worth making it as easy as possible.

I received the two used units promptly and set about cleaning them up. They came with top trunnions and dust-shields. I stripped the kingpin castellated nut and removed the kingpin and trunnion, detaching the dust-shield. Very (very!) mucky but solvent spray followed by detergent bath did make headway.

Stubaxle rear- lower O ring for Dust shield location.

Some headway with cleaning the part

Unfortunately cleaning revealed that at least one of these axles had a problem. Obviously they are not new parts so some signs of use are likely. However the offside stub was badly scored and seems to have had a loose bearing at some point. I don't think it will be usable.

Taper section O/S stub axle badly scored.

Andy was very understanding about this, apologised for the quality of the part and sent a replacement.

I had wanted to use a bench press in order to remove the existing bearings- largey because I now own one! However I was defeated by trying to mount the stub axle securely. It's a very awkward shape and I couldn't get a clean, safe line for pressing. If anyone knows how to do that please let me know. Anyway I reverted to plan "B" which was to use a draw-bolt threaded through each bush in turn as I have done in the past. The usual approach here is to use a suitably sized socket to press the bush, but sockets are always rounded  at their ends and any size transitions are sloped. This means that a socket tends to either slip off the top of the bush, or expand it as its trying to push it out. Once the bush is pushed below the lip of its housing this is no longer a problem,  but it can make that initial push quite tricky- and its definitely problematic when refitting. To avoid this I made up the following two adapters that can slip inside the bush for positive location and have a 90 deg shoulder to press on the  bush. 

Press adapters as made; Large bush 23/26 mm, small bush 23/21 mm

They are sized to slip down inside the housing keeping everything straight as the bush is removed.

Press adapters fit into the relevant bushes- pictured after bush removal! 

These were assembled onto a draw bolt (M8 studding) again using appropriate sockets to pack the thing out. Obviously you need a larger socket on the bush-accepting side and a smaller one on the pressing side. The assembly is shown below- using the removed bush to indicate its position. My drawer bolts are M8 studding but I'm using the roller bearing/thrust washer assemblies from a Draper press and pull kit which can be bought as spares.

Positioning the assembly really depends on where the sockets will locate firmly. I found that the large bush was best pressed inwards, and there isn't enough room for a really deep socket to be fitted there. This meant that the last few mm had to be tapped out with a hammer and drift on the push adapter, but luckily at that stage the bushes were pretty loose and came out easily. The smaller bush could be removed by pressing it outwards and there is enough room for a deep socket in that position. The draw bolt and adapter in use is shown below. 

Using a draw bolt to remove the bushes

This system worked really well and removed all bushes in pretty short order. 

I cleaned up the rest of the parts, one point of note is that one of the dust shields turned out to be partially home made. It will need some repair but seems to be functional. However, I will use a bona fide part for the rebuild if I can get one. I treated both stubs with metalmorphosis and then sprayed them black- I also treated the spare hub I had obtained- taping over all threads and holes- as well as any mating surfaces that shouldn't get paint on them

Both stubs and a hub repainted.

I bought a partial king-pin kit from Ebay- I needed to chase up various other bolts and seals but managed to assemble a complete set for both sides, with new trunnions and bolts top and bottom for rather less than the cost of a new kit. I will use the adapters to fit the new bushes too, but I may need to make an additional piece for the other end of the bush so as to ensure any pressing forces are exerted in a straight line and don't  let the bushes bulge outwards too much as they are inserted.

Insertion press kit as made

I made the kit as above where both adapters will slip easily into the bush- they need to be smaller in diameter than the kingpin as you don't want to get them caught up should the bush bulge inwards during fitting (as it probably will). The larger diameters were made to slip inside the housing smoothly so that they will hold the bolt central in the socket as the bush is pulled home. One adapter is pressed by a socket whilst the other is free to slide along the draw bolt. I used a short length of rubber tubing to hold it against the bush and let it slip along the bolt as the bush moves into place. Sorry to make heavy weather of this but I  hope the diagram below helps!

The adapters were both made to the same dimensions in each bush- if you get 26 and 23mm silver steel the the larger dimensions need pretty much no modification so for the larger bush adapter dimensions* A and B are 26 and 23.5mm, whilst for the smaller bush they are 23 and 20.5mm. Length isn't critical as long as the combined lengths of the narrower sections is less than the length of the bush!
*These are appx I will measure properly and amend asap

With these adapters I still needed sockets to press on both ends- a large one to sit on the outside of the housing and a smaller one that could be pressed in with the other end.  This meant that both bushes were best pressed in from the middle of the housing in an outwards direction since the outer surfaces are flat and smooth and the socket fits well there. When making the adapters, its really important to get a sharp 90 deg step on the pressing ridge, any chamfer here just bells out the end of the bush and it will not fit in like that.  I found these worked well. Using both press adapters the pull bolt is kept centred in the hole and the bushes press in easily.

New bush- oil grooves on one half only and no open ends.

 When fitting a new bush the manual states that the open ends of the grease channels should face towards the stub axle- I suppose to ensure that old used and excess grease is pushed up into the dust tubes where it might still do some good (?). The grease grooves in my new bushes had no open ends and  were only present on one half vertically- as in pic above, the grooves stopped half way down and before the top of the bush. Luckily the instructions also say that the split in the bush should face forwards (i.e. away from the stub axle and towards the wheel). This positions the grooves towards the dust shield side.

Positioning bosh, split faces outwards and grease hole in bush is in line with the nipple hole in the axle

Pressing in the new bush using the adapters

nearly home

in position, bush sticks up inside the axle but is flush with the recess on the other side.

The bushes are pressed in flush with the external surfaces of the housings and protrude a little internally. The remaining bushes were fitted similarly and without problem- the most fiddly part was making sure that the sockets had a fine seating on the stub axle and in most cases it was actually easier to press the bush home from the inside of the stub axle towards the outside as this gave a good seat for the large socket - see below...

Reaming is simple if you have the right tool and I got this two step reamer from MGB Hive- worked very well. As with any reamer- use lots of cutting oil and turn in one direction only. Also I have heard that reamers will cut again if you twist them out (clockwise obviously) so its probably best top pass them through once and then tap them back with a soft mallet.

Starting to ream

Always worrying- swarf coming out mid way.

However the job was very successful so I cleaned up the reconditioned stub axles and swapped all the grease nipples for new.


The top trunnions were a little corroded inside and the new bushes would probably not fit like that. The trunnion  needed careful dressing internally with a half-moon file to remove the worst of this and restore the double conical profile.

inside profile restored

There was also some damage to the top surfaces of both trunnions and kingpins where they were probably levered with a screwdriver in the past. This damage would obviously prevent the shims/thrust washer assemblage from sitting flat so this damage too was carefully filed flat.

Screwdrivering damage to trunnion/thrust washer mating face

Damage filed flat

I will treat the trunnions with Jenolite to stabilise any rust and hopefully prevent more before repainting them. I'll put the hubs and refitting all of this in a separate post.

Progress?

Well I've been struggling on with the MGB. Spent a fortune on parts and its been like Christmas with all the packages arriving here. Still, here is a summary of progress to date:

Rear brakes and hub oil seals. I tackled these exactly as described in the Dr-Doolin.com excellent YouTube video. No pics here because he says it all and my experience differed only marginally as my car has alloy not wire wheels.

I found the brake shoes were virtually new both sides but the N/S rear hub seal was clearly leaking and as a result hub and shoes were very oily. I replaced the oil seal and shoes this side giving everything a good clean. I do have the parts for the O/S but as the shoes were new and seal not leaking I left these for the time being.

I had the exhaust (and the duff mountings) replaced with a new mild steel system (can't afford stainless at present). Vast improvement in both sound and exhaust fumes in the car.

I took my first tenuous steps in carburettor tuning. I had filthy black plugs and colortune confirmed its running really rich. New air filters surprisingly gave a vast improvement and mixture adjustment with filters on also gave a smoother (not smooth) idle.  Finally I attempted balancing, and things are definitely better! I will detail all these procedures later as I plan a carb rebuild anyway. One problem I have though is that when the motor is warm the idle doesn't return to normal but sticks around 2k. The motor will also increase in speed on its own!

Checking various forums shows similar problems are common... The most common cause being  a stuck cable. This isn't the cause in my case (and I'm not sure I believe it when it was identified in some if the documented cases either!). Anyway in my case the effect occurs even if I don't touch the pedal, and when it does both carb throttle levers are solid on their stops. Pressing here doesn't lower idle speed again and blipping the throttle, either by hand directly on the lever or at the pedal, doesn't help either. In order to slow them down the simplest way is to put a hand over the carb air intakes. I have also backed the fast idle screws right off and loosened the spindle clamp bolts as well as all cable connections and it still happens!! This all sounds like an air leak to me but I can't find one. Possibilities include a leaking gasket somewhere or maybe the poppet valves on the butterflies introduced in the Hif4 carb. I understand these are designed to admit air and prevent over-richness when the throttle is snapped shut. However they apparently can stick open  if their springs are weak (which may happen if they get hot). I understand now (too late) that replacing the butterflies with HS4 solid plates is considered preferable. I did seek advice from Burlen Fuels SU shop and was advised to stick to the originals... Seems not to be the best advice and perhaps driven more by the need to empty the stock room... Or maybe that's just my cynicism!! Anyway new valves can't hurt. I am planning a carb rebuild and I have the major rebuild kit and a few extra gaskets to refit everything in case of air leaks so I will describe this later.

I have installed a battery clamp and de-rusted the carrier... Both of which were pigs of jobs as access is really bad... My back may never be the same again! Still, at least replacing the clutch pedal return spring was easy.

I have also started to recondition the two spare stub axles I bought but that really does need a separate post!

The Machine and the tasks ahead!

A note for "Old hands"

Hi Y'all. I'm new to MGBs- I have had several cars and I've just rebuilt my Lotus- but this is a new experience. I'm just not used to being able to get all the parts I need easily- and even with a choice of suppliers! I'm also aware that the world is full of experienced old-hands who love these cars and have worked on them for a lifetime. I'm not trying to re-invent the wheel or teach anyone to suck eggs. I'm learning, and just as I did with my rebuild on the Lotus Excel (see my blog) I'm going to run a blog of my experience here. I'm working alone and it helps to write everything down. It may well read like a "How-to" guide, but its not really that. Its primarily a diary, my own record of what I did, what everything used to look like, how I took it apart and put it back together again and what worked for me.  I'm not recommending what I did and I accept no responsibility for any loss or damage caused by anyone following my methods. After all,  I'm not a mechanic, just an interested enthusiast. If you know a better way to do any of what I've done, then please message me and I will be happy to update the blog.

I do allow advertising on the blog but I'm not connected with any products that might appear there. I'm not paid for recommending any products or components, if I use something I will say whether it was a success or not and that will be my honest experience.

Overall if this blog helps anyone then I will be delighted, but that's not its primary purpose. There are plenty of real how-to guides out there. Please feel free to drop me a line, a word of encouragement or a correction and suggestions for improved methods. Otherwise just read on and enjoy vicariously the "joys" of classic car ownership! You are welcome and your company is appreciated.

Mike


So... lets begin at the beginning!

I have wanted an MGB GT since I was at school... sadly this now means some 45 years!! Redundancy and retirement brought me the opportunity and I found this MGB GT LE through Ebay. The description sounded great ...

MG BGT LE LIMITED EDITION SUPERB CONDITION LOW MILEAGE

"Built in 1979 as one of only number of MGBGT LE. Car stored in collectors show room until 1986 when it was then registered for use of the public highway. This car has not been a restoration project, it is in its original condition with very low mileage. The mileage is a very low at 42,823 New fuel line done but not been calibrated, so will need retuning. Everything else is tip top"

I checked on the previous MOT and it was passed 6m earlier with no advisories.
Similarly the pictures also looked good...

The car was described as having been in a private collection for the first 6 years of its life and subsequently registered for road use in 1986. There were 3 previous owners, but the first two were actually the same person; in both company and subsequently individual guise.

Well there were problems:

Firstly the motor ran very roughly- this was attributed to having fitted a new fuel pipe- this seemed an unlikely explanation but its possible that perhaps balance was upset when the link pipe was accessed at the roadside as an emergency repair. The tyres were all very worn but worst of all there was a gash on the LHS rear quarter and the LHS door mirror was missing. I understand that this damage was done during the currency of the advert so it wasn't visible in the pictures supplied with the ad - although these actually turned out to be  old photos supplied when the current owner had bought the car from a dealer. In retrospect its clear that they were taken in a showroom with other MGBs nearby. Always worth asking that question I think. The damage wasn't however added to the description  although the seller had lowered the reserve price. The engine compartment was grubby but complete.

However the lack of advisories in the MOT and the promise of an un-mucked about vehicle in full original spec (and a good amount of history- all tax discs, MOTs, V5 copies handbook and service book) was obviously tempting. I renegotiated the price  in view of the undeclared damage, and given the rough running arranged for it to be collected and tuned before I risked driving it home. Here I'm grateful to Maidstone Sportscars who collected the car and checked it over for me ... but what they found was a shock- although I believe the description given was made in good faith, the fact remains that it was not exactly "tip-top"!

I received the following list of problems:

4 tyres needed

Jacking points corroded and broken

Rear anti roll bar bushes worn

Rear springs weak

Exhaust blowing, corroded with a broken mount and delaminated rubber doughnut mounts.

N/S King pin worn

O/S wheel bearing worn

Leaking sump gasket

Half shaft oil seals leaking

Oil filter mount-to-motor O ring leaking

Rear brake shoes worn

In addition there was the rough running- they attributed this to a seized carburettor piston and the carb-linkage having been fitted incorrectly. I asked the garage to fix the jacking points, change the tyres and fix/balance the carbs. I was pleased with the work done-- except it didn't change the rough running at all! The cause of this remains a mystery although I still suspect carburation. My pleasure was however tempered, as one fault they hadn't reported was that the fuel gauge didn't work! In the event, they gave me the car back with insufficient fuel to drive to the nearest garage, I ran out in less than half a mile! Still at least they did come and bring me some juice!

So now a bit worried about the state of this car... and it got worse. I took the car to my local MGB specialist (Wey classics, sadly now closed and greatly missed) to get a quote for repainting the rear wing. They  also noted badly corroded rear quarters and warned me that usually these also mean that the sills are likely to need attention- although that isn't going to be clear until they get in there. They also identified a worn water pump (I should have noticed that) and a loose battery. I had arrived fairly chipper and left subdued with a £3k estimate for welding- not including all the repainting!!!

This was a shock! After all I had bought the car largely because it was in original condition- but chopping out great chunks of metal means that even that will no longer be true. The trouble is that the best point of this car is also its worst point- simply, its not been touched!

I was concerned that the first garage inspection had revealed only corroded jacking points (which are now fixed) but had not identified any problems with the rear quarters, so to be absolutely sure that this work was really needed I sent it for a "pre MOT" at my local garage. This resulted in a mixed bag of findings- there was some good news, but sadly it did confirm the need for rear quarter panels. They also  found that the state of the exhaust, headlamp alignment and the loose battery  were also "fail" items. On the plus side it downgraded the worn kingpin and bearing to very badly worn bottom trunnions (both sides) and found that both the rear brakes and anti-roll bar bushes were passable.  Other items were noted but not currently MOT significant:- a broken clutch pedal return spring, corrosion on rear floor near spring hangers that needs to be stabilised, and holes in inner front wheel arch.

So all this investigation then has defined my workload. The repairs will now cost more than the purchase price but overall I will still end up with a well-priced example and I should learn a lot on the way. Anyway she is far too beautiful to scrap!

Already done...

Tyres replaced

Jacking points welded

To get done...

Replace exhaust (new mild steel system and fixing kit bought from MGOC)

Replace both rear quarters and fix any more corrosion that this reveals and respray.

To Do...

1. Service timing, ignition and carburation- compression test the motor. This is fairly urgent because the multitude of oil leaks might result from excess crankcase compression- and that could indicate far more serious motor problems.
2. Lower kingpin trunnions (I will renew both kingpins and top/bottom trunnions as I don't want to have toi take this apart again soon)... and since there is a query over at least one of the wheel bearings, I will renew both and their hub oil seals, this is easiest if done at the same time as the kingpins. 
3. Replace rear brake shoes and half shaft oil seals (tube axle). Again these are conveniently done together.
4. Sump gasket and water pump- since the coolant needs draining before the front of the motor can be raised to access the sump bolts, these two jobs can be done together. Whilst the oil is drained I can also replace the oil filter and  the O ring sealing the filter mounting against the block. 
5. Replace battery clamp- derust and treat battery carrier.
6. Derust rear floor, inner wheel arches and general rust eg below rear bumper, stabilise and repaint.
7. Possibly replace rear springs and rear ARB bushes (apparently not needed for MOT).

I will be working my way through this list in this blog- mainly as a record of how I took things apart and how to put them back together again!

Read on with me if you dare!!!

Should add I turned up this little nugget of my cars history... it was sold at Carfest 2015 although theres no record of the price. It was then described as condition 109/135 and had 40869 miles on the clock.

0