Marcel.
I used GoodParts TR6 suspension bushings in the TR4A. I can't remember if it
was just the rear parts that had special washers with slight recesses in them
to catch and hold the steel tube bushings or if the front has them too, but I'm
with Jack in that I think that once assembled the bolt is fixed and the
bushings/trunnion rotate . The castellated nut and cotter pin allow you to get
it all very tight, but not so tight that it doesn't want to move. I also used
GoodParts Steering rack aluminum blocks but had them machined down to get a
reasonable compromise with regards to bump steer. You may be able to do better
than I did via bending the arms but I was happy with where it ended up. Look up
GoodParts stuff at:
https://www.goodparts.com/shop/index.php?productID=275
Bob Kramer
rkramer3@austin.rr.com
---- Marcel Van Mulders via Fot <fot@autox.team.net> wrote:
>
>
> _____
>
> Van: Marcel Van Mulders [mailto:van.mulders.marcel@telenet.be]
> Verzonden: dinsdag 10 maart 2015 19:04
> Aan: 'Jack Wheeler'
> Onderwerp: RE: [Fot] TR4A front suspension.
>
>
> All the parts are TR-4A-TR6, so the trunnions are 3° (all TR trunnions that
> have removable trunnion bolts are handed, trunnions with pressed in pins can
> be 0° or 3°).
> "...the lower trunnion should rotate around the bolt..." If I understand
> what you mean, I don't believe this is correct : the trunnion bolt is
> clamping the distance pieces (short pieces of steel tube that slide over the
> bolt and rotate in the outer wishbone bushings) onto the trunnion and hence
> the bolt, trunnion and distance pieces should rotate together and only the
> wishbones can rotate in respect to the bolt (and trunnion and distance
> pieces). I have assembled the suspension in this way, eliminating thus the
> play of the trunnion on the bolt and this is the reason I had to drill new
> holes , more to the rear, in order to get the upperr end of the uprights
> between the outer ends of the upper wishbones. All parts and also the
> chassis seem to be all right. Maybe I get it wrong anyway with the
> assembling of the suspension parts
> Marcel.
>
>
>
>
> _____
>
> Van: Jack Wheeler [mailto:jwheeler1947@yahoo.com]
> Verzonden: zondag 8 maart 2015 23:40
> Aan: Van Mulders Marcel
> Onderwerp: Re: [Fot] TR4A front suspension.
>
>
> Do you have the TR-4A uprights and trunions? The TR-4A trunion is just the
> brass piece that fits in between the lower wishbone arms and a bolt slides
> through it, instead of the fulcrum pin (pressed into the trunion), as you
> would have had on your TR-3. The lower trunion should rotate on the bolt,
> and the wishbone arm bushings. There is a left and right hand, and when
> properly installed, you should have about 3 degrees of positive castor on
> both sides. I raced a TR-4A for 25 years, so I know the suspension
> intimately! Good luck.
>
> Jack
>
>
> _____
>
> From: Van Mulders Marcel via Fot <fot@autox.team.net>
> To: fot@autox.team.net
> Sent: Sunday, March 8, 2015 5:35 PM
> Subject: [Fot] TR4A front suspension.
>
>
> In June 2014 I bought Bob Kramer's TR4A racecar after I crashed my TR3 at
> the Zandvoort circuit (The Netherlands). It's a great car and it will get
> better. Of my TR3, I only kept the engine and overdrive dogbox Overhauling
> the front suspension, I found that the lower trunnion was moving on the bolt
> instead of the bushed lower wishbones : the distance pieces in the wishbones
> where shorter than original, so the trunnion was not clamped by these
> distance pieces when fastening the bolt. Correcting this, the upright has
> less play now, only a little in the trunnion, and this upright with
> balljoint can't be forced anymore between the outer ends of the upper
> wihbones, the balljoint is 1/2" too far to the rear. Turning the upper
> wishbones to the rear (by moving the fulcrum pin) isn't a good option,
> because binding will occur. I've drilled new holes for the brackets for the
> inner ends of the lower wishbones : the suspension is moving without any
> binding now but I don't know if I will leave it like that. I wonder if
> something is wrong with the uprights? (less than 3° caster?) If I measure
> the caster, I find 2.2° on both sides, but probably that isn't proving
> anything. The chassis is as new, no damage. Any idea's someone?
> Another question : trying to get at zero bump steer, the best I get at by
> moving the steering rack is a J : the wheels are toeing in when lowered more
> than 3 cm below ride height (minimal to 5cm, then more and more toe in).
> Bending the steering arms to the outside, almost touching the brake disks
> now, has straightened the J a little. Is it possible to eliminate the bump
> steer completely, or have we(TR4A-TR6) to accept some bump steer in the
> least important part of the suspension travel?
> Marcel.
>
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