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Old 18th December 2015, 00:13   #1
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Default MM550: Issue with steering precision & turning radius

Hi guys,

I am the new and proud part-owner of Samurai's old MM550 (see here (Hardtop MM550 : A family friendly offroader joins Team-BHP)).

I have two fundamental gripes with this vehicle.

1) The steering has extremely poor precision due to excessive play and some bump steer.

2) The turning radius is a lot larger than expected.

A closer inspection of the steering linkages pinpointed the drag link and the bellcrank assembly to be the root cause of the free play in the steering.


For #1, my mechanic suggested to replace the old grease-type drag link with a new sealed ball-joint type drag link, and also rebuild the bellcrank with a new bushing kit. I do agree that this is a good short-term solution, but perhaps experts here can shed some light on whether this will develop play rather quickly, or its a good way to go?

As far as bump-steer goes, I suspect the "dog-bone shackles" have something to do with that since they change the angle of the track rod relative to the axle. Which vehicle's shackles can I fit if I prefer to have silent-bloc rubber bushings rather than the crude grease pins?

For #2, I have no idea. How can I get more wheel cut angles? Different steering box? Wider or open knuckle axle?


I would like to understand what my options are to resolve these issues. A rundown of what components are needed and approximate cost is really appreciated!

Last edited by ananthkamath : 18th December 2015 at 00:16.
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Old 18th December 2015, 04:57   #2
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Default re: MM550: Issue with steering precision & turning radius

Get Hold of ARKA - he has more experience in this subject, also done a few experiments and did come out successfully too.

Open Knuckle is always better in terms of what you seem to aspire but factor in the cost too.

http://www.team-bhp.com/forum/4x4-ve...d-upgrade.html (My MM540XD upgrade)

Last edited by shekaran : 18th December 2015 at 05:00. Reason: included link
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Old 18th December 2015, 12:52   #3
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Default Re: MM550: Issue with steering precision & turning radius

Quote:
Originally Posted by ananthkamath View Post

1) The steering has extremely poor precision due to excessive play and some bump steer.

2) The turning radius is a lot larger than expected.
1- Best solution is to put a new steering system, right from box to all links and ends.

Regarding bump steer, check if the steering damper is in good shape, replacing that would also help.

2- As far as steering radius goes, easiest option is to use offset wheel rims to increase the track width.

If budget is not an issue, you can opt for the open knuckle set up, this will help. But the whole diff set up needs to be changed.

Keep in mind it is an old jeep design which is designed towards ruggedness, not towards user friendliness.
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Old 18th December 2015, 13:13   #4
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Default Re: MM550: Issue with steering precision & turning radius

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Originally Posted by ananthkamath View Post
1) The steering has extremely poor precision due to excessive play and some bump steer.
Hi Ananth, as Jaggu mentioned, if you are planning to keep the jeep for a long time, change the steering box and all the ball joints and bushes to brand new.
For bump steer, remove and reset the closed knucle assembly. If possible fit a steering damper. Your fingers will be safe.
Quote:
2) The turning radius is a lot larger than expected.
You will need more track width and a steering box with more travel. Two ways to go.about it is to get offset wheels or better get a 57" open knuckle front axle assembly. Along with it, you can change the steering box to MRCBT. (Bolero pick up type ) ones.
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Old 18th December 2015, 15:55   #5
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Default Re: MM550: Issue with steering precision & turning radius

Thanks guys. I read through Arka's thread, it was very interesting and informative.

Basically my conclusion is that there is no easy way to achieve tighter turning radius without changing both axles. How much will this cost approximately? My budget is substantial but not unlimited .

Quote:
Originally Posted by Jaggu View Post
2- As far as steering radius goes, easiest option is to use offset wheel rims to increase the track width.
Hi Jaggu - I already have 0 offset wheels. Not sure how this will affect turning radius without also increasing the pitman arm travel? Isn't that the limiting factor?
Quote:
Originally Posted by dhanushs View Post
For bump steer, remove and reset the closed knucle assembly. If possible fit a steering damper. Your fingers will be safe.
Hi Dhanush - by reset did you mean rebuild the kingpins etc to remove free play? There is already a steering damper fitted. I will check its condition. I guess we're talking about two different things when referring to bump steer. I meant to say that the vehicle wanders whenever the front wheels go over small undulations in the road surface. I think this is probably a geometry issue since the front steering drag link and track rod are not perfectly parallel to each other.

Last edited by ananthkamath : 18th December 2015 at 16:05.
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Old 18th December 2015, 16:12   #6
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Default Re: MM550: Issue with steering precision & turning radius

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Hi Jaggu - I already have 0 offset wheels. Not sure how this will affect turning radius without also increasing the pitman arm travel? Isn't that the limiting factor?
Positive offset wheels (to avoid fouling) plus adjusting the stopper bolt, is what i had in mind.
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Old 18th December 2015, 21:06   #7
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Default Re: MM550: Issue with steering precision & turning radius

Hi Ananth,

There are two ways to fix your steering problem.

1) The cheaper way to fix it is to replace your steering box with the one from the Armada. It reduces the steering effort and the play to a great extend and doesn't cost much.

2) The better and expensive way is to install the Manual recirculating ball type steering box used by Mahindra in all heir Thar DI/Bolero Pick up range of vehicles. This requires some chasis alterations and needs to be done by an experienced shop.

For the turning radius, you can consider off-set alloys that will help to some extend. You can also adjust the steering stopper bolt to allow maximum turn.
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Old 19th December 2015, 01:13   #8
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Default Re: MM550: Issue with steering precision & turning radius

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Hi Ananth,

There are two ways to fix your steering problem.

1) The cheaper way to fix it is to replace your steering box with the one from the Armada. It reduces the steering effort and the play to a great extend and doesn't cost much.

2) The better and expensive way is to install the Manual recirculating ball type steering box used by Mahindra in all heir Thar DI/Bolero Pick up range of vehicles. This requires some chasis alterations and needs to be done by an experienced shop.

For the turning radius, you can consider off-set alloys that will help to some extend. You can also adjust the steering stopper bolt to allow maximum turn.
Hi 4x4addict - Thanks for the super-useful info. Armada type steering is basically a bolt-on recirc ball type, correct? It still retains the bellcrank but uses a U-joint on the steering input shaft and sealed tie-rod ends on the connecting rod (drag link). Is that the one you're talking about?

In regards to the MRCBT, can I still retain the current axle or does it need to be 57" open knuckle type?

Positive offset alloys are probably out of the question. I'm thinking about downgrading to the army 16" steel wheels on the next tire replacement.

Good tip on the steering stopper bolt. I had no idea such a thing existed. Will look into it ASAP.
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Old 21st December 2015, 22:33   #9
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Default Re: MM550: Issue with steering precision & turning radius

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Originally Posted by ananthkamath View Post
Hi Dhanush - by reset did you mean rebuild the kingpins etc to remove free play?
Hi, Yes.
Quote:
I think this is probably a geometry issue since the front steering drag link and track rod are not perfectly parallel to each other.
I think you have the OE steering system? Also, how are the leaf springs cambered?
In regards to the MRCBT, can I still retain the current axle or does it need to
Quote:
be 57" open knuckle type?
You can retain the current axles. But, if you are retaining the current axles, I would suggest to replace your existing steering box, linkages and bushes to new.
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Old 21st December 2015, 22:53   #10
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Default Re: MM550: Issue with steering precision & turning radius

Yes I have the OE steering system. I believe the leaves have stock camber but the "dog bone" shackles provide about 1.5" of additional ride height which obviously steepens the drag link angle in front view. I suspect that if the steering play is eliminated, the bump steer can actually be felt through the steering wheel.
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Old 23rd December 2015, 09:25   #11
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Default Re: MM550: Issue with steering precision & turning radius

Quote:
Originally Posted by ananthkamath View Post
Yes I have the OE steering system. I believe the leaves have stock camber but the "dog bone" shackles provide about 1.5" of additional ride height which obviously steepens the drag link angle in front view. I suspect that if the steering play is eliminated, the bump steer can actually be felt through the steering wheel.
I have run with bigger shackles, and leaf springs cambered till 7.5" in the front, but, I haven't experienced bump steer. But yes, with Spring over axle vehicles, yes, but this isnt that high.

So, I would suggest to rebuild the king pins and sort out your steering set up.

Also, do you find the bump steer more than a jeep with a similar chassis and steering? Please do test drive one more specimen and see. Because, the C section chassis has a tendency to wander off and also create bump steer.
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Old 23rd December 2015, 09:42   #12
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Default Re: MM550: Issue with steering precision & turning radius

Ok, I was able to take a closer look at the Jeep today.


1. Both stopper bolts have a lot of room at full lock which means that something else is limiting the wheel cut angle, not the axle. My guess is the steering box runs out of travel. Will an Armada box resolve this? Note lack of witness marks on either the bolt or the knuckle flange, indicating these parts have never touched like they should at full lock.
MM550: Issue with steering precision & turning radius-_20151223_092109.jpg
MM550: Issue with steering precision & turning radius-img_20151222_123749233.jpg


2. The drag link tie rod end seems to have contacted the anti-roll bar. The second photo shows the d-block support bracket for the bar mount. Wouldn't an MRCBT box occupy the same space as this bracket? (See center of 2nd photo) All this makes me doubt whether this bar is OE fitment or if something is bent.
MM550: Issue with steering precision & turning radius-img_20151223_092207.jpg
MM550: Issue with steering precision & turning radius-img_20151222_123150515.jpg


3. This is the front view angle I was talking about. This is due to suspension being raised over stock. I don't think a stock MM550 has this steep of a drag link angle. My shackles are only 4.75" long, so I don't see how that alone is making a huge change to the ride height (I.e. not as much as 1.5" like I said before).
MM550: Issue with steering precision & turning radius-img_20151223_002714.jpg



Quote:
Originally Posted by dhanushs View Post
So, I would suggest to rebuild the king pins and sort out your steering set up.

Also, do you find the bump steer more than a jeep with a similar chassis and steering? Please do test drive one more specimen and see. Because, the C section chassis has a tendency to wander off and also create bump steer.
Thanks, I will work on it. The bump steer is definitely more than a stock old MM540 that I drove. It's a very subtle difference, but it's there. i feel it as a slight lateral wiggle when one of the tires goes over undulations. Perhaps it's just a matter of me adjusting my expectations.
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Old 23rd December 2015, 21:58   #13
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Default Re: MM550: Issue with steering precision & turning radius

You need a full steering system rebuild. King pin bearings, tie rod ends, knuckle kits.

Then move on to the bell crank and steering box.

junk the stabiliser bar.. pointless.
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Old 24th December 2015, 15:24   #14
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Default Re: MM550: Issue with steering precision & turning radius

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Originally Posted by prabhuav View Post
You need a full steering system rebuild. King pin bearings, tie rod ends, knuckle kits.

Then move on to the bell crank and steering box.

junk the stabiliser bar.. pointless.
prabhuav - Thank you! We'll take a closer look at the kingpins. I think I want to retain the stabilizer bar as much as possible since this is a highway + off-road vehicle rather than pure off-road. Just puzzled why it contacts the drag-link though.
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Old 28th December 2015, 18:39   #15
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Default Re: MM550: Issue with steering precision & turning radius

Quote:
Originally Posted by ananthkamath View Post
have two fundamental gripes with this vehicle.

1) The steering has extremely poor precision due to excessive play and some bump steer.

2) The turning radius is a lot larger than expected.

A closer inspection of the steering linkages pinpointed the drag link and the bellcrank assembly to be the root cause of the free play in the steering.
Hi Ananth,

Please check the following

1) Steering Pipe and Bushes in the Cabin

2) Check if the Steering Box has an UJ on the input shaft. Or does the Steering Pipe come through the firewall and bolt to the Steering Box?

2a) Check the Steering Box for Play on the Pitman Arm.

2b) Check if all the steering Box Bolts are tight, check the J Clamp or the J Clamp Replacement Bracket on the chassis.

3) Check the Bell Crank this is usually the culprit since the sector shaft is held by a woodruff key which is inadequate.

Change the bell crank to the Mahindra Major or Army MM550XD type.

4) Check the Tie Rod Ends(Ball and socket joints) 7 in total for the Bell Crank system

5) Check the Steering Damper, the one mounted on this vehicle is very poorly done.

6) Check King Pin Bearing and Kingpin

7) Install the Felt and Rubber Knuckle Kit.

Regards,

Arka
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