Page 18 (Updated 08-Nov-2008)

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Wheels

- DIY Front Wheel Alignment
- Brakes: Fluid Change, Tuneup, Balancing
- ABS
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Free Service Manual, Free Download.....see FAVORITE LINKS -page 26- FAVORITE LINKS
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Front Wheel Alignment:

 

Overview

Front wheels need alignment for example after car has been on loan:), yourself hit pavement edge or after shock change. If alignment is not done, wheels wear quite soon from one edge. Another result will be poor driving if alignment is not ok. This toe in -alignment is easy DIY job, next I explain THREE ways to do this. The camber and caster alignments are important and should be checked when possible, but these seldom change [needs accident, strut change] and one can often 'commute' without.

However, if after toe in -alignment your car behaviour in curves does not satisfy you, its time for 4 wheel alignment.

Workshop 4wheel Laser alignment systems are nice and accurate and pls go there if po$$ible. But if the basic thing is to check front wheels toe in angle: that measurement can be done even with vacuum cleaner pipe. I did this once, then went to this fancy 4w laser adjustment: the adjustment was exact, no need of further adjustment! After that I have always aligned with a sliding stick, measuring tire inner sides for rear vs. front 1mm gap (or whatever is suggested for that vehicle).

Check for DIY shock absorber change on page 25.
Check here for basic wheel alignment info -LINK: ...click here...
Four wheel alignment (buy or DIY??) info -LINK: ...click here...

Before alignment, check that wheel bearings, lower ball joints and steering tie rod joints are in good condition. Also check axle rubberboots, and each joint rubber condition. Raise and try to shake wheel using as much force as you can. Possible lower ball joint fault may need prying wheel assembly upwards with a crowbar. If no clearance is found, all wheel mountings etc. might be good and you can proceed. If not, correct any free play before adjustment. Next is needed a flat surface.

The following text explains DIY procedures for alignment.  To ensure your results, go to alignment and see how it went...  and if you succeed, save next time by trusting in your own work!
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Three ways for DIY alignment:

...Read all through and decide!

 

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Alignment - First case:

Requirements:

You need two straight plates, two measuring tapes, that is all.
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Front wheel Toe In -alignment: Depending on vehicle, the red lines that represent wheel angle, should have certain mm difference measured at BLUE arrow points.

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- Two straight plates. One touching the RH wheel outside, the other touching LH outside - on even floor [I use wheel size glass panels for their straightness, you also may buy or mfg metal plates. They have to be ! absolute straight]. I also used two shims to clear from the wheel cover, arrows 1 and 3 in the next pic.
- Two measuring tapes crosswise under the car; one front of wheels (A.), second behind the wheels (B.). Green arrows show the tape start points under LH alignment plate.
- Tape ends are placed under RH plate bottom edges running under LH plates. (The thin yellow arrow points how the tape turns 180 degrees under the car...)
- During measurement, wheels should straight forward - NOT be turned in any angle.
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Glass plate against RH wheel: plate makes contact to wheel at points 1,2 and 3.

 

Note: as the glass panel is angled outwards, the soldertool is leaning against the panel to keep it touching the wheel...

- Read the toe in measurement on the tapes passing under LH plate edges. Accurate reading is seen just under the plate edge. (Verify first that your measurement tapes are equal, use equal, narrow tapes if possible)
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Read measurements from the both tapes at the plate edge, here seen tape B.

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In Maxima, the tape A reading should be 1mm less than tape B. If it is something else, adjustment is needed.

 

Turn wheels to the left to access the RH connecting rod. The rod has a locking nut that has to be opened. After it is opened, the inner part of the rod is loose and can be rotated to shorten/lengthen the rod. It can be done from the hexagonal part with a proper tool. Typically no more than ½ turn is necessary. After re-measurement, the adjustment is fine tuned again.

Note 1.: between adjustments, before new measurement, the car should be moved a little.

Note 2.: This single adjustment results in steering wheel zero point misalignment. If that matters to you, both side wheel rods should be adjusted equal amount simultaneously... or steeering wheel should be re-positioned afterwards.

Note3.: Check out that the tierod rubber shield will not stay warped after adjusment. If it is, loosen and straighten it...

Locking nut (1.), place for tool adjustment (2.), adjustment = rod rotation (3.).

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Alignment - Second case:

 

If no tools are available, plates or tapes, the measurement can be done 'with any stick'. In such case I use two tubes where one slides inside the other. At/After first measurement A., I tape them together to lock the measuring stick at this lenght.

Measurement between wheels, inner distance A. and B.

 

First find a 'stick' that fits tight on the front = A. Next measure distance B. on the exact profile point (see next figure). On measuremen B., there should be small gap, half millimeter is just about right as the measurement does not happen at the sweet point [=at halfway tire] in Maxima (1mm toe in) case.

Measurement between wheels, inner distance A measurement point at rubber tire profile 'ring' which point is also used in B. -measurement.

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Alignment - Third case:

 

OK, now u get u laser. First buy that 20$ laser tool...

AND u get u Camber measurement. Figure out how...
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Setting up the laser against the wheel; maybe better arrangement would be better...?

 

Measuring the Toe In:

- First measure A on the wall; distance between Laser spots. If you have two Lasers the better, otherwise you must mark the spot on the wall.
- Next push car backwards. The distance is dia= wheel diameter.
- Measure laser points again from the wall to get distance B.

Calculate Toe In: B - A = Toe In.

Toe in measurement setup.

 

Camber:

If your tool contains the Laser spread -lense, you can measure also the Camber -angle: Draw an angle tool on paper, hold the paper straight and read the angle from the paper. The laser's setting is critical: its alignment with wheel has to be ensured better than shown here.

Measuring the Camber angle

 

Btw. You've got endless variation possibilities here. A guy who likes iron more than lasers, can substitute the laser to a long rigid iron bar... Also no wall is needed, you need just something to project the laser beams.

As all alignments have been done, quick checking the Camber PLUS Toe In would be possible by turning the laser tool at 45degrees to the ground, and measuring the distance for future reference...
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BRAKE SYSTEM

Std brake issues are well documented in manuals, here I pick only few important issues mostly neglected by maintenance shops. (See Favorite Links at page 26 )
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BRAKE Fluid change, BLEEDING

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Overview:

Brake Fluid should be replaced every 2-3 years. If not, ambient moisture seeps in and rots the system from inside. Floating dirt reduces its effectiveness and causes brake line, cylinder corrosion. In extreme cases, continuous long braking, water in the fluid starts to boil. Resulting vapor in the system may cause total sudden brake loss.

Open hood and check out the reservoir: Fresh fluid is colorless; replace immediately if color is brown.
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Replacing the fluid, steps 1 to 8 :

1. Take batt negative connector off -OR- Turn the ignition switch OFF and unplug the electrical connectors from the ABS actuator under the hood, RH corner. Shield reservoir area, engine bay with cloth or used newspaper.
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Shield for accidental spill, Pull out reservoir filter
  2. Clean all dirt from around the master cylinder reservoir cap. Remove the cap and filter. Fabricate a small (?half quart) plastic bottle: drill a hole in its cap, push a tight fitting 8" hose in. Install cap. As bottle is squeezed, hose end dipped into reservoir bottom and pressure released, produced vacuum sucks brake fluid & dirt into the bottle. As vacuum has been used, raise bottle up, press and dip hose into reservoir again. Suck whole reservoir empty.
  3. Re-install the filter. Fill the master cylinder to the proper level with clean, fresh brake fluid meeting DOT 3 -or- DOT 4 specifications.

Don't leave the master cylinder or the fluid container open any longer than necessary. Be careful not to spill brake fluid on painted surfaces. Wipe up any spilled fluid immediately and rinse the area with clear water as brake fluid is effective paint remover and destroys fast all rubber parts.

Rusty Fluid vs. Clean Fluid, reservoir at right is clean & colorless

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4. Clean all the bleeder screws. You may want to give each one a shot of penetrating solvent one week before trying to loosen it. Seizure is a common problem with bleeder screws, which then break off, sometimes requiring replacement of the part to which they are attached. When bleeder screw breaks, use brake hose connector for bleeding or repair system (insert guide to collect used fluid into a jar).

5. Prepare to collect outcoming fluid. Commercial collect jars, with backflow block valves are handy, not necessary. Attach its clear vinyl tubing to the bleeder screw on the farthest wheel bleeder screw (here left rear wheel cylinder or caliper.) [Next phase: left rear, next left front, next passenger side front.]

Notes:
- The axle boot (blu) has to be checked against brittleness, repaired ASAP if any crack found.
- See CV axle boots, page p.25.
- The ABS sensor ring (here yel) has to be cleaned if there is excess dirt buildup.
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Front Caliper bleeder screw, 10mm spanner,
bleeding jar.
  6. Have your helper SLOWLY press the brake pedal. After pressure is applied , open the bleeder screw, and allow the fluid to run through the tube. Close the bleeder screw before the pedal reaches the end of its travel. Have your assistant slowly release the pedal. (Fluid change: Repeat this process approx 8 times for both rear wheels, six times for both in front, or until no air bubbles appear in the now colorless expelled fluid.) Check/add fluid [through reservoir filter].
  7. ABS: If you are taking air out after repair, Repeat the procedure on the other wheels in the following order (Maxima). In other cars, look at the system: idea is to take longest line to ABS actuator first, proceed towards shortest. Following Maxima -93 FSM -guide has all this upside down, have fun:

1993-94 ABS models:
1. Right front caliper
2. Right rear wheel cylinder or caliper
3. Left front caliper
4. Left rear wheel cylinder or caliper

8. In the end, repeat steps 2&3 just to remove any new floating dirt.

8XX. In extreme cases air bubbles does not want to come out and pedal keeps feelin mushy:
- Open all bleeder screws simultaneously, let system bleed while filling the reservoir. Close after half quart has flown out. You may re-use the liquid only after all outcoming fluid is new. (Total system capacity is somewhere near one small fluid bottle 300ml eg. third of a quart).
- Try bleeding at different points in the system tubing (like rear brake balancer connections).
- Buy 4 pcs of Brake bleed fluid bottles, insert in all wheels, open bleed screws, and start pumping. Later go through the procedure if necessary.
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BRAKE Caliper Tuneup

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As caliper has been first opened, worn pads taken off for brake pad change, pry carefully the rubber lip ajar from top -side of the caliper piston. Use injector (or some smooth tool) to insert the special grease. First lift the rubber open with a blunt screwdriver: NEVER use std vaseline or grease!

Inject also to the two caliper guide dust shield rubbers to ensure caliper free float in the future [std grease is ok here].

Test caliper free float by installing the caliper assembly back without the disc: as caliper sits tight, the caliper part containing the piston assembly has to move freely (see pic above, red). If it is sticking or has sideways play, it definitely has to be repaired. As worn caliper sticks and does not sit aligned, brakes pads will stick and wear out soon. Mpg goes down, discs will get hot. Eventually wheelbearings will be fried. One indication of this worn/sticking -condition is unevenly worn pad pair.

Caliper guide rubber (false colored grn), red Caliper piston, yel piston rubber

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Pad Thickness:
Maxima std rotor minimum thickness is 20mm; if worn more, replace. Pad thickness minimum 2mm (+base).
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BRAKE balancing:

 

Is this your car? Proceed to balance u brakes...

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Balancing the Braking force; front/rear:

Load sensing valves:

Basically the load sensing valve balances your brakeing forces based on how much the car is loaded. The more load in rear, the more braking power will be boosted at rear wheels. Test driving alone, hit the brakes, medium force: if front dives hard/deep, wrong adjustment (take into account if the car has worn front shocks). If shocks are good, brakes balanced, there is no-s-dive... If rear tends to 'sink' first, the valve(s) are tuned too much to the rear. If one rear corner tends to 'sink' first, its valve is tuned to open too much.

Rear brakes should always engage during braking, "half" force of front with heavy load. The front calipers have been typically built bigger, so the actual braking force is already always bigger - even without adjusting valves.

Balancing Brakes; the load sensing valve. The 3-gen Maximas (-89-94) independent suspension needs two valves, one for each rear wheel.


Balance Adjustment:

 

If rear brakes do not engage during light braking, the issue is the twin load sensing valve adjustments. They are located behind rear axle assy. The valves adjust the amount of pressure divided between rear/front brakes. A load sensing valve is adjusted with the nut (at the coilspring ends, see above) which tighten/loosen the valve via linkage. One end of the system is attached into the chassis, other is on the wheel axle: load and road conditions continuously adjust the mechanism & adj valve. This affects the rear brake fluid pressure.

If adjustment is incorrect - it makes vehicle braking dangerous on slippery conditions. Refer to FSM; with added 1300lb rear =trunk load, measured brake fluid pressure should be:
- front pressure 710psi , rear 550-700
- front pressure 1400psi , rear 740-940
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This is the way how FSM directs the balancing, but test drive on snow or loose gravel will give good enough results to guide the adjustment: all brakes must lock simultaneously regardless of load. Test with load AND also without. (disable ABS by taking ABS fuses out during test, see page 5 ).
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RESULTS from balancing, tuneup - FYI
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'Wine' gets Maximized better by the year; year 2005 I did Brake fluid change & caliper rail&piston greasing, 5k miles later, braking power is up almost 5%. (Used to be at Front 2.60) At state inspection the acceptable deviation percentage between LH/RH -wheels for Front&Rear brakes is 30%, Handbrake 70%; my Maxima has now zero 0% !!! These dynamometer inspection results for my maxima (Jan/06, 85k miles) below. These numbers also clearly show that system LH/RH -balance settles itself much better when well lubricated.
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Dynamometer Tested Braking Power:
.......2005...... | ..........2006...... | ..........2008 :
2.93 / 2.87 .. | .. 3.02 / 2.97 .. | .. 3.02 / 2.60 .....LH / RH -Front
1.30 / 1.38 .. | .. 1.34 / 1.33 .. | .. 1.50 / 1.50 .....LH / RH -Rear
1.55 / 1.80 .. | .. 1.69 / 1.72 .. | .. 1.50 / 1.50 .....LH / RH -Handbrake
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The explanation for changes in 2008 inspection numbers:

In the -08 inspection it was found that my RH front shock absorber had broken and lost 50% of its capacity. This resulted in dramatic drop of measured braking efficiency from
previous year 2.97 >-to-> 2.6 ... (see page 25 shock swap)

The rear braking power increase is because I manually adjusted the balance [no pressure measurement], see above. Now when braking, the nose will not 'hit' down...

 

 

How Bad Shock Absorber affects Braking:

The actual 2008 shock absorber test results; see how RH shock failure affects braking:
.......2008......
88 / 38 .....LH / RH -Front
84 / 88 .....LH / RH -Rear

Note: Last year all those shock tst numbers were below 80 ... tells smtg about these vague numbers - lousy measuring...

See Shock Absorbers at page 25

[one dynamometer product link: http://www.gotovis.com/rbm.htm]
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ABS Anti locking Brakes

 

ABS Computer (trunk roof) :

ABS Computer in the Trunk roof; At right the computer box connector.

I Took off the computer box, cleaned and added contact grease to each pin; see page 14 . Very little grease to each pin, with a tootpick edge. These pins are tinned, and the tin oxidizes very easily, and also is so soft that cavities form during one year under the pin pressure. The ABS computer grounding wire goes is inside the cabin, attached on the top of the rear shelf. See p.10 for groundings.

Self Diagnostics:

ABS self diagnostics test utilize a led in the box which is hard to see; tape a shiny piece of metal at 45degree angle to mirror the diag led at the computer box bottom.
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ABS & other onboard computer Self Diagnostics p.21
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ABS Actuator assembly (under the hood) :

ABS Actuator Assembly under the hood; connector cover opened at right.

I Took off the connector cover, took relays off, cleaned and added contact grease to each pin.
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ABS Schematics:

ABS electronics diagram (general) and hydraulics circuit diagram at right.

ABS actuator wirings (engine compartment). Computer box Power supply, fuses and wirings.

 

 

ABS Wheel Sensors:

Each sensor should be between .8k - 1.2k Ohms; the connector for the front wheel sensor is just behind the strut tower in the engine bay - you can follow the wire from the sensor through the strut tower and back behind it.

ABS Sensor, front wheel. Sensor wiring schema at right.

Uninstalled ABS tacho ring (LH), Wheel bearing, Seal and ABS Sensor (at right).


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Known Problems:

- buzzing sound coming from under my hood after the car was turned off. Sound coming from passenger side of the vehicle towards the front of the car, part of the abs system. ... abs warning lite is turning on as well.

Inside ABS actuator assy theres a pump, and its relay has shorted (=ON always). Open the plastics cover and check out. Maybe hitting the relay with screwdriver handle [hammer will solve all problems] will loose those contacts... Take connectors/relays out, clean contacts, reinsert. If no help, replace relay.
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ABS control in GM:

"If an antilock brake sensor malfunctions, the system can kick into gear at low speeds, taking control away from the driver and leading to longer stopping distances" ...but not to worry, its only in Canada: "...GM notified the National Highway Traffic Safety Administration that it was recalling 150,000 trucks in Canada..."
Read Detnews 26-May-05 article: http://www.detnews.com/2005/autosinsider/0505/27/C01-195410.htm
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How the Earth was measured: "He stood, and measured the earth: He beheld, and drove asunder the nations; and the everlasting mountains were scattered, the perpetual hills did bow: His ways are everlasting." -Habakuk
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