Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing How hard can it be? - Fitting Brake Reaction Bars

Well done. Let us know if you see a difference

Great work

Not a direct compassion as I also changed the shocks and fitted the steering damper but the car does feel more solid at the front so an all round improvement.

I had them ready, for a DIY job on MattMog.


Even thought I wouldn't have to drill because there are screws provided in the chassis.


But then MattMog was rejected for the front suspension. (MOT)
So asked my garage owner to place them together with the new kingpins.
But drilling had to be done, maybe not with another supplier?

The Morgan feels like a much more stable car, the best adjustment you can make for almost no money.

On a separate point, when did Morgan move from having alloy stops on the chassis for the wheel to hit on full lock to removal of those and a cut out on the chassis rail to prevent it hitting?

It’s the chassis indent just behind the fixing for the BRB.

BRB's Really! they are Cross head braces and stop the top of the cross head moving either fore or aft.
Do they make a difference? You bet they do!

Firstly: Under hard braking the cross head suffers a rotational force the tends to try and tip the top of it forward. Not just as a force which remains stationary but it actually moves directionally forward. This results in the axel tube remaining in it's true plane as its stabilized by the lower stays but the top tubes from the center square cross bracing are pushed forwards at their outboard ends. This alters caster, cator and tow settings and creates that juddering sensation felt through both the body of the car and the steering wheel. This is as a result of the shimmy created at the tyre as it loses and regains traction much like ABS in feel but hugely undesirable!

Secondly: Driving on the ever increasingly poor and broken surfaces we find ourselves on these days, every time one side or the other of the cross head receives a shock through the suspension it upsets the steering geometry and causes what is akin to bump steer with the associated symptom of shot shock absorbers. That rattle at the steering wheel. This is caused by the high frequency spring effect of the top tube resuming its correct position.

So, fitting cross head top bracing stops a lot of this effect. It was fine when the cars were made for a different era of motoring but they now require a far greater level of stability and certainly finesse!
How do they actually work then? Well they work in both compression and tension in that they help prevent all but the most extreme rotational forces on braking and acceleration from having to great an effect on the top tube and thus the suspension element of the front end geometry. They also have a damping effect when extreme shock happens at one or both sides of the car in that they reduce greatly any spring vibration that the top tube would suffer from in recovery of that shock.

Most drivers will feel a 'more solid' sensation that these braces will achieve. They will quickly forget just how jittery and unpleasant their steering was before fitting them and will quickly go on to seek more finesse out of these old chassis designs that the classics have! Those wise amongst you who have described them as the cheapest and best improvement you can make have absolutely nailed it!

Just a couple of other things i picked up on. Those cars with the one shot oiler system removed have not always had pillar changes and the oilway is not adequate for greasing purposes . use a thick oil in a grease gun if this is the case.

For the post 2011 cars with adjustable camber and having dome topped pins. I agree with those who say that the cross head braces should be fitted above the conical washers. the minute amount of movement at this point were the camber to be adjusted would be easily accommodated by the brace. If this exercise is undertaken, it is first vital that the oiler bolt is loosened. The only difference that it will make not being fitted directly above the top shock absorber mounting plate is its slightly different location point on the chassis rail! and as all cars vary slightly here that's not an issue. I also feel that putting anything that irregular and not fully supporting under the conical washers is asking for trouble!

Actually while I'm here I should mention a little about shock absorbers too. On the rear with leaf springs you can get quite technical and use adjustable shocks to really good effect. On the gentle surfaces you will be able to retain a smooth and pleasant ride but the adjustable shock absorber will allow you to set a compromise for those pot holes! Yes! you can't iron out all events and retain a comfortable ride but a good balance can be achieved in the limited 42mm of spring travel! However there is a cheaper way and that is to fit a good mid range effect shock absorber and if you have the cars with the suspension hoop mounting, I think post 1979 and with mono tube shocks ask Roger for a set of his progressive bump stops. These work in conjunction with the rear suspension helping to smooth out that jarring bottoming out as it adds another suspension element much like the rubber cone suspension employed on the original mini and is hugely cheaper than SSL 5 point, yes nowhere near as sophisticated by by heck damn good nonetheless!

On the front suspension, believe it of not the rebound springs take care of a lot of the damping and the shocks in the standard range are really very weak and only provide a subtle damping effect. Fitting hugely expensive adjustable items to standard cars can't really achieve much whatever the setting you set them too! More, the reality is the steering/driving set up is via the springs and you will chase it forever if you are not satisficed with the standard set up. Really the only way to go is with progressive rate springs if you want more. shock absorbers are described by their name, they damp shock effect and slow wheels dropping into holes etc.
If you start with soft springs and set adjustable dampers to a hard setting you will get a harsh drive on less than smooth surfaces, yes, you'll get some slowing of body roll but it won't help the handling or roll in a cornering situation.
Now lets look at those 180lb foot springs, that'll stiffen it up wont it. Well yes, for the track which is really smooth! Harsh ride again on general road driving as the suspension won't give on a light car and the shocks won't even come in to play!

Better to fit a shock absorber that will work well with the initial soft end of a progressive rate spring and into the start of the stiffer area where the spring will then take over. Then as the spring relaxes back into and through its early soft compression, again you will benefit from the action of the shock absorbers. So in conclusion, with this set up you will get the best i.e. most achievable comfort for general road driving and if you push it now and then, a good balanced and well behaved car that won't catch you out!

An interesting thought provoking couple of posts sewin, most of which I agree with.

A few of your comments I'm unsure of though. Under acceleration the upper reaction bars (can we call them that ) don't do much, indeed the front suspension tends towards being unloaded unlike under heavy braking.

I would argue that the conical washers are best placed directly under the top oiler bolts to best take account of the adjustable camber angle that such cars allow and as such are tightened down. This also places the reaction bar closer and in more direct contact with the cross arm it's helping support. Speaking of the latter I note that those offered by Wolf Performance have the upper end of brace terminating in a shallow welded bush rather than the plain flattened tube of MMC items. The illustrated fitting instructions for these also concur with my thoughts. BTW I did hear that Cain had a pair of conical washers explode whilst tightening down, but put this down to lack of lubrication on assembly. As well as thoroughly greasing both halves I do assist these by orienting as far as possible with an initial set to take account of angular variation they are designed to take up.

Regarding front shocks the front end with its limited travel needs all the help it can get. For this reason I opted for the SSL RS kit and furthermore the Spax gas assisted adjustable shocks they normally include, selling the AVO adjustables I had fitted before. This after sorting out the rear with SSL dual rate coilovers to far better suit the factory 5 link rear on my Roadster which of course highlighted the front deficiencies, although I understand most folk sort out this end first.

Whilst the front shocks may well have little work to do, especially if the rebound spring is adjusted to zero pre-load static as with RS kit, there is a very noticeable sweet spot when setting them up by gradually increasing damping, when rebound travel suddenly comes under control and surprisingly to me offers a more comfortable ride over bumpy surfaces.

Richard,

The SSL RS system from Dan is undoubtedly the optimum choice and hard to argue that it can be bettered if retaining a sliding pillar system, so then I'm in total agreement with you that its possible to tune in a sweet spot with an adjustable shock. but that will and can only be a personal opinion. And as I had said the SSL 5 point or the MMC version again achieves the best option available for fine tuning. Here I was trying to show a more reasonable price option can be found for the middle of the road user.

The conical washers accommodating camber adjustment I feel are absolutely best fitted after the angle has been set at the top of the pin and especially as most new stays come with the reinforcing washer added and the flex at the flat folded end of the stay offers little resistance to being bolted down and won't compromise the patency of the conical washers in that position so we will just have to hold to our different views on that one.

For every action there is an opposite and equal reaction, so when the flex occurs at the cross head tubes although putting a rotational force in place which wants to move the outer top tube forward the return force is mostly equal so in a situation where a driver is pushing the car between extreme braking and acceleration it follows that there will be a compressional force applied to the stay as without damping it cannot be a tie rod in isolation. Otherwise why would one be required to take the moments around such bracing in say bridge design, making sure it won't fall down that is, or fail through fatigue.

The shock absorbers available for the Morgan are all really very weak in action, somewhat akin to the resistance/return action of an average steering damper. Given to most mechanics even when new they would tell you that it's faulty so disregarding my views on the rear shocks re. adjustment I still stand by my view for the front option.

Bringing the stay on the chassis closer to the cross head by positioning above the conical washer set you infer making it less effective, I totally disagree with, that. It moves it forward by about 8mm and with the forces involved I can't quite see the level of efficiency that could be lost. However one thing it does achieve especially if you grind a relief angle at the chassis end to fit the the stay as close to the vertical chassis member as possible is to align it with the factory chassis relief for full lock steering thus preventing the tyre fouling it.

For my final thought, anyone wishing to spend the large amount of cash that a fully fitted SSL system front and back costs, especially if you can't fit it yourself! , Here my suggestion would be to change the front suspension out to wishbones as without that change you really wont get the drive you are after

Thanks for reply sewin. Sorry but I cannot agree with your thoughts on the conical washers though. They are designed to self align to accommodate the angle of the kingpin and the surface it's being bolted down to. This can only happen efficiently by them a) being well lubricated and b) being directly under the bolt as it's rotated to tighten, allowing them to self align. This is how mine were fitted by MMC when car was built with spec'd reaction bars and as mentioned above how Wolf Performance suggest they should be fitted, as well as making plain engineering sense.

To suggest other than above shows a misunderstanding in how they can and do work when installed correctly.