Upgrading the rear end

[ryana83]

So I had a couple of days off from work in a row and decided to put some parts that have been laying around on the car. I have GTP arms, new bolts, brake bias plugs and new loaded rear calipers that I attempted to put on today.

This is what I started out with.


Started getting into the rear control arms.


Got the passenger side on easily, the driver side is still being a pain.


For all the people afraid to cut their arms to adjust the camber and toe, this is what was taken off the arms.


This is the porportionig valve with all the hardware removed.


This is what was left after trying nicely to get them off.


A picture of the stock bias plugs.


A comparison of stock and new bias plugs.


Installed bias plugs.

 

[ryana83]

Continued


Also turned the rear rotors at work.


Also decided to paint them in high temp black to match the car.


Up close view after all the prep. This is the first coat of paint.

And to my suprise, I went to Pull-A-Part today to look around and what did I see just sitting there all alone......A police grill

It was only $15! A coat of paint and it will look awesome.

This is what I spent my dad today doing. Hope you guys enjoy.
Any question or comments are appreciated.

Thanks,
Ryan

 

[DHMag]

excellent work man. i did mine all in the same day too, but i didnt buy bias plugs or new calipers

i do have a request though. on the pic of the control arms ends that you cut off: could you include the part number of the arms you bought and also specify how much of the arm you cut off ? perhaps use Paint to add the writing on the picture. i believe it would be an excellent resource for those who havent done it and are not getting definite answers from the Forum. and if you didnt mind, id like to save a copy of the pic to use when the need arises.

btw, your driveway looks like mine...pretty aggregate stuff.

 

[ryana83]

Some Answers

On the control arms, you cut about 1/2 inch off both of the ends that thread into the adjustment sleeve. The arrows are just for reference, not the actual spot.



It is real intimidating until you do the first one and find out that it will still thread. Just clean up the threads, twist it back in and put some anti-seize on them and you are good to go.

For the arms, I bought them awile ago, so I don't know about the part number. On my invoice it says part number (GM Part #: 10262699) but it probably has changed. I got the arms from GMPartsDirect.com also.

Save away on the pictures guys, I am here to help. It took me a long time to do it because I wanted to do everything at once, and do it right. Just take your time and things should go smoothly.

P.S. The aggregate really sucks when you are wrenching on a car. Man would I **** for a normal one, but in the subdivision we live in, it is manditory.

 

[SHO Type U]

Anyone know the current part # for these rear control arm?

Happen to know the width, thread pitch, length of the arms after being cut?

?

 

[60kmaintenance]

What are the bias plugs for? Er what was wrong with the stock system?

 

[yamahaSHO]

The bias plugs allow full flow to the rear brakes at all times. The stock system cuts flow when the rear lifts up and when you make hard left turns. I will be installing plugs, but adding an adjustable Wilwood bias valve.


ryana83 - Where did you get your loaded calipers? Did they come with the brackets?

 

[shoteen95]

Correct me if i'm wrong on this...

But regular taurii used drum brakes in the rear, and if i remember correctly, the drums needed less fluid or pressure (or something like that) to operate...

As our cars came stock, the rear brakes arent used to their full potential..the bias plugs fix that

EDIT, curse you jason for you reply one minute before me!

 

[yamahaSHO]

I believe some regular Taurii came with rear discs, but I am not positive. Also, the bias valves are mainly a carry-over from the Taurii that did not have ABS.

It can be very dangerous to use bias plugs in the rear if you don't plan your braking system and suspension accordingly. I've locked the rear w/ABS on track ('96 fronts and stock rears) and I have been with Chris when his rears started to lock and bring the rear end around (12" PBR's in front, stock rears). The ABS did kick on in both cases, but the rears still have a split second to lock and cause excitement. Not to mention, if the ABS does activate, your stopping distances will be longer.

Here I am locking the rear...

 

[shoteen95]

yikes, that looks exciting!

i've seen a few early gen 3 sedans (not wagons) with rear discs..

did the gen 1 or 2 wagons have rear discs?

 

[Shoaz]

I will be installing plugs, but adding an adjustable Wilwood bias valve.

You know you gotta replumb everything to do that, right? i.e., no longer split diagonally, but split front/rear.

But regular taurii used drum brakes in the rear, and if i remember correctly, the drums needed less fluid or pressure (or something like that) to operate...

As our cars came stock, the rear brakes arent used to their full potential..the bias plugs fix that

The bias plugs don't fix a problem with the way the bias is set, they just eliminate the modulation that the valve currently does as the left rear suspension flexes. Whether eliminating that modulation is a good idea or not is a matter of varied opinion.

Personally, the best thing to do for a track car is add a manual bias control valve, but that requires replumbing the brake system and probably deleting the ABS. I _like_ ABS, even for a track car, and I _like_ the idea that the bias valve automatically moves the bias under hard braking. You get more efficient use of the rear brakes that way.

IMHO, the only really squirrely thing about the factory valve is that it's only hooked up to one side of the suspension. As can be seen in the pic above, in RH turns the LH rear suspension compresses, which moves the brake bias to the rear and increases the likelihood that a rear wheel will lock under trail braking. In LH turns, the opposite happens and you can apply a lot more brake before the rears will lock. This assymetry in the behavior is not really what you want. I adjusted the bias valve on my silver car when I put the BMR control arms in so that under trail braking in RH turns the inside rear just starts to activate the ABS. I think the result is that I don't have as much rear bias under straight-line braking as I could, which means I lose some efficiency in those conditions.

But I don't want to lose the ABS and I don't want to replumb the entire system for a manual control valve, so I live with it.

With bias plugs you get maximum rear bias under all conditions, which, at least in my case, would make the likelihood of the rears locking under trail braking even higher. Likelihood of locking the rears under hard straight-line braking also goes up, which is also not desirable. In straight line braking that valve seems to help; I don't think I've ever had rear-wheel lockup in straight line braking.

 

[yamahaSHO]

You know you gotta replumb everything to do that, right? i.e., no longer split diagonally, but split front/rear.

My thought was to get two of them and install the at the rear of the car. Making sure both are adjusted evenly.

Even still, you would only have to cross some lines at the ABS unit. Easier said than done of course.

 

[gosho89]

You know you gotta replumb everything to do that, right? i.e., no longer split diagonally, but split front/rear.



The bias plugs don't fix a problem with the way the bias is set, they just eliminate the modulation that the valve currently does as the left rear suspension flexes. Whether eliminating that modulation is a good idea or not is a matter of varied opinion.

Personally, the best thing to do for a track car is add a manual bias control valve, but that requires replumbing the brake system and probably deleting the ABS. I _like_ ABS, even for a track car, and I _like_ the idea that the bias valve automatically moves the bias under hard braking. You get more efficient use of the rear brakes that way.

IMHO, the only really squirrely thing about the factory valve is that it's only hooked up to one side of the suspension. As can be seen in the pic above, in RH turns the LH rear suspension compresses, which moves the brake bias to the rear and increases the likelihood that a rear wheel will lock under trail braking. In LH turns, the opposite happens and you can apply a lot more brake before the rears will lock. This assymetry in the behavior is not really what you want. I adjusted the bias valve on my silver car when I put the BMR control arms in so that under trail braking in RH turns the inside rear just starts to activate the ABS. I think the result is that I don't have as much rear bias under straight-line braking as I could, which means I lose some efficiency in those conditions.

But I don't want to lose the ABS and I don't want to replumb the entire system for a manual control valve, so I live with it.

With bias plugs you get maximum rear bias under all conditions, which, at least in my case, would make the likelihood of the rears locking under trail braking even higher. Likelihood of locking the rears under hard straight-line braking also goes up, which is also not desirable. In straight line braking that valve seems to help; I don't think I've ever had rear-wheel lockup in straight line braking.

I've read the bias plugs are not desirable on the '89 (non abs) system. What are your thoughts? Currently I have 12.5 baers on the front and BMR arms with the factory bias valve clamp to one. After a hard lap the rear rotors read 350 degrees. The rear is a little twitchy under hard braking in a straight line but trail braking is comfortable. Any ideas? It didn't seem so bad before changing to a 22mm front bar.

 

[oh_SHO]

Yes regular Taurii did come with rear disk brakes. It was an option for them. Most likely on LXs and sables. All the parts are interchangable. Infact I have a nice extra set of e-brake cables that a SLO was kind enough to donate to me.

 

[60kmaintenance]

Yeah now I'm more confused then ever..... I never really had a problem with non ABS brakes, you just got to feel when your gonna lock up..... Well of course that gets awfully weird when it's an extream moment.

How does the ABS unit work, when does it kick in ? That'd probably help me understand more.... I haven't really planned on upgrading my brakes to much, I'm happy I already got non-solid rotors. Brakes are far from being a easy priced upgrade :/

 

[yamahaSHO]

How does the ABS unit work, when does it kick in ?

The ABS works when a tire locks. It pulses the brakes to bring you to a stop and allow you to have control where you would otherwise skid and possibly bring your rear end around. When ABS activates, your stopping distance is actually longer because ABS does not hold the tires to the point of losing traction. It is a little harder to control not locking up the rear than the front. Brake upgrades are not that expensive at all... $550 for my 13" brakes.

 

[60kmaintenance]

$550 is a lot of money though......

Uh I know what ABS does, but I don't know how it WORKS, like what triggers it etc on a SHO, I got no clue. (I'm not talking about from a point of view of driving, I mean what mechanical componets recognize what and how etc)

 

[yamahaSHO]

You asked when it kicks in.... Then what triggers it....

The ABS works when a tire locks. It pulses the brakes to bring you to a

There are ABS sensors that monitor the ABS rings on the axles... When the tire lock, the magnetic sensor pics this up.

 

[60kmaintenance]

Oh ok, that explains it to me better.... Well when you plug the bias, you'll get more powerful brakes, fix the odd handling, but you'll have a greater chance of a harder lock up ? In what way would the plugging stop the ABS from function? Could you a switch to make the ABS always come on (intercept the wire and make your own switch to by-pass and turn on, or off, or leave stock?)

How are the current brake lines wire up?

Sorry I wasn't more specific.

I do realize ABS can stop the accelration time.... There for you could be better off with out it, if you where good at not locking up the wheel (brake upgrades being the best way with big rotors right). However from the way you speak of it, it doesn't matter until a wheel locks up ?

Curiously I wonder how a Lincoln 95 ABS system would work.... It's DIFFERENT the least to say, the way the brake pedal reacts etc.....

 

[yamahaSHO]

I give up... I'm going to go enjoy my 13"/11.6" brakes now